Some doctors prefer their patients have a low residue diet for 2 days and clear fluids for one day before the colonoscopy, but most now seem to have given away the low residue diet and just use clear fluids for 24 hours prior to the procedure instead. It totally depends on your doctor's preference.

With a 1:30pm appointment, you should expect to have either all or half the bowel prep the afternoon/evening before.

My appointment was early in the morning, so my prep was all done during the day/evening before, but because you have an afternoon procedure, you might find your doctor wants half the night before and half in the morning.

Once again it depends on your doctor's preference.

Everyone needs to starve prior to theater to prevent intra-operative complications and the starving time also depends on doctor preference. Some would say nothing in your stomach for 6 hours prior to your surgery, and some say 4, but it's important to drink lots of clear fluids while you can to prevent dehydration. I got in a supply of sports drinks so I didn't deplete my electrolytes with the trips to the bathroom.

You should get all of this information as a printed information sheet from your doctor before your operation, and if you don't get one ... then ask.