I'm trying to put in an 1/8 rest before a shot. Any tips?

Welcome to the forum.

Use C. on the beat you want the 1/8 rest, then put the chord with the shot on a push on the next beat.

C. will rest all instruments. ^Dm7.. for example, would push the shot on a Dm7 chord ahead by an eighth note.

For example, if the shot is on the AND of beat one, you would enter: C.,^Dm7..

Also, for future help, you should post questions in the BIAB forum for PC or for Mac. This forum is for giving general tips, and does not get as much attention for problem-solving requests.