Basics: DADGAD is an open Dsuspended 4th tuning, so it is neither major nor minor in nature, but can easily be played either way....

To play in the major scale on most strings use the 2nd and 4th frets.

To play in the minor scale, use the 2nd and 3rd frets. (generally... individual mileage may vary)

To play a D chord use 1 finger, on the G string at the second fret (this is actually a D 5th) then hammer down the other fingers on other strings at the 2nd and 4th frets for different accents (if you want a major sound, see above for minor sound.

To play an easy G(-ish) chord, fret the low A string at the 2nd fret.

For the A(-ish) chord, play x02200 or 202200.

Should get you started...

Play around with it. It's fun.