Root on A string
x577xx
D5 is the D power chord. Its notes are D and A. No third means no major or minor quality. Mute unused strings carefully.
x577xx
10-12-12-x-x-x
Numbers show frets from the low E string to the high e string; x means don't play that string.
Every D and A on the first 12 frets. The filled dots are the root, D. Build your own shape from any nearby group.
Other D chords
Other power chords