First of all I have heard that you should start with an acoustic but I don't like acoustic in general. Is this true??
If the music you want to make is electric, you will never get there and love music with an acoustic. If the music you want to make is acoustic, you will never get there and love music with an electric. I own both. I love both. I prefer the electric.
Last question, How should I get my guitar set up for easy playing??
Reordered because this gets deeper.
"Easy playing" depends a lot on the kind of playing you want to do. If you want to play lead guitar, like Angus Young of AC/DC, you would want a flatter neck and lower action, which allows you the ability to bend more. If you want to play rhythm guitar, like Malcolm Young of AC/DC, you would want a little more bow in the neck and higher action, so the strings can ring freely without clanging on frets.
I recommend medium picks and strings (.010 sets) until you can express a need for either heavier (I want to detune and djent, or be cool like SRV) or lighter (I want easy bends for country or blues, or be cool like Billy Gibbons).
Doing a setup is fairly easy, and there are guides available online, but if you're getting a pro setup, explain the kind of playing you expect and they should be able to make it work.
A setup is, more or less: truss rod > new strings > string height > intonation. The scariest is adjusting the truss rod, but if you do quarter turns and give it time, even that shouldn't be too bad. And, esp. if you stick with the same gauge of strings, you shouldn't have to redo it when changing strings.
What does intonation mean and how can I check it??
Intonation means how close the note you're intending to play is to the note you're actually playing. If you play slide, or steel guitar, or fretless, or violin, or most other instruments, this means training your ears and hands. If you play guitar, it is a mechanical process.
We guitarists mostly mean that the octave note at the 12th fret is the same note as the octave note at the harmonic at the 12th fret. With the electric, this involves pulling out a screwdriver and an electric tuner. With an acoustic, this involves choosing the right strings, maybe cutting a new bridge, and eventually just saying "this is close enough".
Either way, you can't fully tune a guitar. Between physics and even temperament, it just isn't going to work. But you can get close enough.
Next, I should look at the quality of the guitar especially the neck, fingerboard and the frets right?? The knobs and switches should also be good?? Any specific things I should notice?? Can anyone recommend a simple tune or chord that I can play to compare tone and quality of pickups??
Plug it into an amp and move the switches and pots to every position. (Terminology break: the knob is the thing that you touch, but the potentiometer, or pot, is the thing that is part of the circuit.) An older pot may have dirt and cruft in it, and be scratchy. There is electronics cleaner that can help, and new pots are like $4 and some soldering, but if you don't want to do that, don't buy that guitar.
For the neck, the biggest watch-out I can think of is a dried-out fretboard, which will shrink some and have sharp annoying ends of frets sticking out the side. Some time and a file will rectify that, but again, if you don't want to do that, don't buy that guitar. You can get perfectly acceptable $100 guitars these days, a gift from Free Trade and the CNC gods, so there's no good reason to get started with a fixer-upper.
If you're learning, you don't have the trained ear yet to tell good tone and pickup quality. Don't stress on tone just yet. And best of luck.
