Happy new bike!
If you haven't found the optimal seat position, this is an easy visual aid.
Dialing in the saddle height for a comfortable fit? Put a 1/2" piece of tape on the seat post to use as a reference. Masking, electrical, duct tape, any will do. Place it on the seat post, maybe an 1" above the frame if there's room leaving it in place, when raising or lowering, over the course of a couple rides. This could take a few days, the tape will hang right in there for you.
An easy up grade, lights. Enjoy!