I bought a ukulele recently and have tuned it using a tuner.But , I have a doubt.When I hold the 3rd fret 4th string for the C chord I am unable to hear the sound of the same string i.e it is muted , the rest 3 strings are audible and clear. Likewise, for D chord , I heard only 1 string and the rest 3 are muted, for B chord , I hear no sound since all 4 strings are muted. How can I overcome this, please let me know Just for info : It is a concert GCEA Ukulele .
The first step is to check to see what is causing the muting. Actually, this is just a good exercise in general to clean up/troubleshoot one's playing technique.
Preliminary checks: First, play all the open strings, one at a time. Doesn't matter how you pick or pluck, just do them all individually. Do they all sound cleanly? If not, your ukulele has a problem. Be sure you have tuned the strings to the correct octave (the G-string should be high or low depending on what type of G-string is being used); if tuned an octave too low, the string will be very loose and bend too easily (if an entire octave too high, it probably will have snapped already!). More than likely, the open strings all sound cleanly, so proceed to the next check.
C chord: Start by fretting the 3rd fret of the A string. Pick it by itself. Does that sound clean? If it is muted, then either your instrument is set up poorly or you will need to work on fretting technique. Comments pointed out that the fretting finger should press down between two fretwires, ideally just behind the wire that the string will contact. Do not allow the edge of your finger to spill over the lip of the fret, as this will begin to deaden/muffle the string and dirty up the sound. You may need to press down with more force, particularly if your strings sit high above your fretboard. Check to make sure that your fretting hand is only touching the strings that it is fretting; press straight downwards on the 3rd fret to avoid accidentally brushing against an adjacent string and muting it by mistake. The thumb can be on the back of the neck for support, or the palm of the hand can cradle the neck. Both work for this chord. If it is not muted, then strum the entire chord. Since the C chord only uses that one finger, if the strum sounds muted now, then it is likely that your strumming technique is muffling the string (or your good fretting technique is going out the window as soon as you strum). Make sure that no part of your strumming hand is resting on any of the strings, and you may need to strum harder/faster across the strings to get all the notes to sound cleanly. Think of strumming through the strings, not stopping afterwards.
If the strumming worked, then it should work with enough practice to become consistent at it. Now on to the next one.
D chord: First, I will troubleshoot the 3-finger grip for the D chord. Start by fretting only the 2nd fret of the G string with the index finger. Does this note sound cleanly? If so, move on to fretting only the 2nd fret of the C string (middle finger). Next, only the 2nd fret of the E string with the ring finger. If all of those can be fretted and picked cleanly, try adding two of them at a time. Then all three, and be sure to take enough time to position the fingers correctly. Make sure each finger can feel the string in the center of the pad before pressing down to play it. You may need to angle the fingers slightly diagonally to fit the fingers in the same horizontal fretspace - rotate the wrist so that the fingers point away from the headstock rather than perfectly perpendicular to the strings. If the fingers feel cramped, one option is to substitute the pinky finger for one of the three notes. Since the pinky is usually the smallest finger, this may help with spacing. Another option is to switch to a larger ukulele, since small ukuleles make claustrophobic fingerings tougher. It may also be wise to consider learning the one-finger partial barre D chord grip if this one is simply not working out. Once this all works cleanly, strum it and it should be good.
For the one-finger version, you need to take one finger and lay it flat along the 2nd fret. Then concentrate the pressure onto the G-, C-, and E-string area of the fretboard, and try to lift the finger off of the A string as much as possible. If done correctly, the three strings will all be sounding cleanly and the open string will not be muffled by the fretting hand. This can be tough for some players, but some find it to be easier than the three-finger version. Do whichever is more consistent for you. You will also need to press down pretty hard, which means it will be easiest if the thumb of the fretting hand is pressing from behind on the back of the neck close to the area directly below the fretting finger.
There is another alternative that I have occasionally seen players use for the D-chord, which is using the thumb of the fretting hand to wrap around the back of the neck and reach over to barre the G-, C-, and E-strings from the other side of the fretboard. I'm not a huge fan of this personally, but it does work for some people. While you may catch some flak from purists for thumb-fretting, it does produce the correct chord, so it may be worth an investigation if nothing else works for you. Not many ukulele chords benefit from the use of the thumb, but this is a case where being able to reach over does avoid needing to collapse the knuckle. I still recommend learning the other two methods if possible because the thumb grip makes for slower chord transitions (the entire hand has to move when going from thumb grips to a chord that needs the thumb on the back of the neck).
B chord: Go through the same process as the D chord by starting with single notes, then combinations of the rest, until all of the notes at once will sound cleanly. Take your time. If issues arise, make sure that the thumb is right below the fingers on the back of the neck for this chord so that squeezing the neck is easy. Keep the fingers perpendicular to the strings for this chord grip regardless of whether you are barreing the second fret or collapsing the knuckle like in the D chord. If you aren't sure how hard to press, press as hard as you can and see if that works. If that works, then you need to be pressing harder than before. If not, something else is the issue. Make sure that the fingers are pressing down as vertically as possible, and avoid letting the fingers on the G and C strings lay horizontally over the E and A strings. They may be causing some buzzing or muting.
The problem seems to be happening on the fretting part, which means you will likely need to practice fretting notes cleanly. Make sure you are pressing down vertically and with the tip of the finger, and right in between the two fretwires. There are lots of ukulele resources available online that would be very helpful, especially for beginners, and you may even have an instructor or friend who can help position the fingers correctly for you to demonstrate.