There are not too many beats in the bar, what is confusing you is that some notes are lasting while other are being played.
You can see it as two groups:
the non-dotted notes, each one lasting one beat, so 3 beats total
the dotted notes, each one lasting one beat and a half, so 3 beats total.
I would note have written this way, but more something like: ...
In the first Am chord, all except the lowest A note are quarter notes, of which there are 3 in each measure in a 3/4 time signature. This probably makes sense to you if we for now ignore that low A and the dotted E (the 2 on the D string in tab).
The trick is the dotted A note in the first chord, which has the length of 1.5 quarter note. Looking at the ...