Knight to D7

I was playing around with the D7 chord (0 2 1 0) and I remember seeing a video of Patrick's where he plays a pretty basic version of Red River Valley with just that chord using a combination of open and fretted strings, but did not explain exactly which strings to pick and which ones to fret and so on. I was practicing this morning and it took a long while, but I figured it out! this makes me feel good about myself because I thought it was so awesome that I could do that after having the banjo for only a matter of months. Now I have to tackle getting my hands to do different things easier and maybe faster, and once I get that down pat maybe I'll be able to sing without messing up.