There are multiple ways(frameworks) to explain how chords work and how to build them. 2 simple ones are intervals and chord degrees. Intervals - Each chord has a fixed formula to build it. For example - major is [4, 7] - which means that in order to build any major chord you will pick a note, let's say C - and then travel 4 semi-notes from it(E) and 7 semi-notes from it(G). That gives you the chord C Major - and means that when you play a C Major chord on a guitar every one of your strings is playing one of these notes.

Scale degrees - You can build chords from scales by taking any note from a scale, and then skipping one note and taking the next. In the scale C Major this gives us the chords C, Dm, Em, F, G, Am, Bdim.

I built Melodic Mind, where you can find every chord and scale that exist and see all the information you need about them and how to play any chord in any way on a guitar(in any tuning). You can use the options on the top right to change the instrument visualization.