Major triadic chords for complete beginners...

Each note up or down (white or black) is called a semitone.

To make a major triadic chord do this...
1) Pick a base note for the chord (e.g. C)
2) To get the next note count 4 notes up the keyboard (both black and white notes) - in our example that is E.
3) To get the next note count another 3 notes up in our example that is G.

To get a minor triadic do the same but count 3 in the first step and 4 in the second - so C minor is C, D# and G - just one notes difference.

There are then 'inversions' of the chord (e.g. transpose the C up an octave (12 black and white notes so its the next C up the keyboard)