Please help me out a bit

Can someone tell me how you know what scale to use with what chords? Or at least the basic idea if its super complicated to write out. Any help would me buch appreciated. Thanks.

A is a handy Key on the guitar:

These are the notes of A minor pentatonic: A..C..D..E..G. - Five notes.

They will harmonise over Am....Dm.....Em..or A....D....E..or A5...D5...E5..

These notes are found all over the neck.

To begin with play them around the Fifth fret and the 17th fret

You will notice they form a pattern on the frets.

This pattern occurs again and again in different keys on different frets.

Originally Posted by: GramboA is a handy Key on the guitar:

These are the notes of A minor pentatonic: A..C..D..E..G. - Five notes.

They will harmonise over Am....Dm.....Em..or A....D....E..or A5...D5...E5..

These notes are found all over the neck.

To begin with play them around the Fifth fret and the 17th fret

You will notice they form a pattern on the frets.

This pattern occurs again and again in different keys on different frets.

So you can play a minor pentatonic over 3 major chords? Like Am penta over A,D,E? Are these the only 3(9) chords that I can play Am penta over?

Probably not. i'm basically a blues player and am concentrating on recording.
Some Guitarists will no doubt join in soon and they will know

The notes of A minor pentatonic are the same notes as C major pentatonic - but in a different order.
So I think C major is another chord that will harmonize with A min pent.

A-A#-B-C= 1 and a half tones

E minor pentatonic is the the same notes as G major pentatonic

E - F - F# - G = 1 and a half tones - same rule