How to go about writing this song (on guitar)?

My Internet friends had this brilliant idea. Doing a collab. And upon
hearing that I take guitar lessons, it was decided that I'd play
guitar.

I figured it wouldn't be a problem because I can play pretty well. But
then the first part- the drums, was recorded. I guess the drums were
done first because the drums keep the rhythm and whatnot, but since
they came first they get the advantage of /setting/ the rhythm. Now
it's my turn to add in my part, but I'm not sure how to. At all.

I had some great ideas, but they seem to fall apart when I try to put
them with the drum track. I don't want to make the guitar perfectly in
sync with the drums because that'd be weird, but it seems like if it's
not perfectly together then it's horribly different.

So does anyone have any advice on what to do next? :/