Welcome to the forums,
@Dick!
See page 27 of the
PSR-E360 Owner's Manual, particularly the square labelled "Easy Chords."
For major chords, press 1 key-- whichever key is the root of the chord (C, C#, D, Eb, etc.).
For minor chords, press 2 keys-- the root of the chord, plus the first
black key to its left. For example, to play a C# minor chord you would press the Bb and C# keys at the same time; or, to play a B minor chord you would press the Bb and B keys at the same time.
For seventh chords, press 2 keys-- the root of the chord, plus the first
white key to its left. For example, to play a C# 7th chord you would press the C and C# keys at the same time; or, to play a B 7th chord you would press the A and B keys at the same time.
For minor seventh chords, press 3 keys-- the root of the chord, plus the first
black key and the first
white key to its left. For example, to play a C# minor 7th chord you would press the Bb, C, and C# keys at the same time; or, to play a B minor 7th chord you would press the A, Bb, and B keys at the same time.
Although the "easy chords" are handy to use, it's actually better to learn how to play chords using full fingering, where you press all or most of the keys that form the desired chords. I say "all or most" because oftentimes you can omit one or more keys from the chord and the keyboard will still be able to correctly recognize the chord-- but only certain keys can be omitted from certain chords, otherwise the keyboard won't recognize the chord correctly.
I have a PDF document of some pages from Yamaha manuals showing the 35 types of chords that Yamaha styles can recognize, but I'm not able to attach it from my iPad, so I'll attach it later today from my desktop.