wow, thnx Cryptic! I got this little theory book which is really great and helpfull, only it's not that detailed in chord construction and progression

allthough I have some questions

is it always the root, 3rd and 5th note that you take for a chord? and why is that?

and with a C-major (--C-E-G-G-E) ah... I see now, lol, so you only play those three notes in that chord, is there a differents in how the notes are arranged? like for instance 2 times G, 2 times G and one time C as it's being played right now

let's see:
D-major (----D-A-D-F)
E-major (E-B-E-G#-B-E)
F-major (--A-F-A-C-F)
G-major (G-B-D-G-D-G)
A-major (E-A-E-A-C#-E)
B-major (E-B-F#-B-D#-F#)

ah I finally understand, why the root note is so important, because it affects the intervals you gotta pick in order to make a chord :)