Chords are 3 or more notes played together, following some common patterns.
Major Chords
1, 3, 5
G Chord has the G in the lowest spot.
Major Scale Whole whole half whole whole whole half
The 3 is the least important note in the chord.
3 doesn’t always have to come between 1 and 5.
Minor Chords
Minor chords have a flatted 3.
1, 3♭, 5