Do I need to remove this cover to use my bed fully?

No. The tri-fold design means you can fold individual panels back or roll the entire cover up without taking it off the truck. Partial or full bed access without disassembly.

What kind of tools do I need to install this?

Basic hand tools — wrench, screwdriver, maybe a drill. It mounts at factory points, so no cutting or welding. Plan on a couple of hours if you're working solo.

Will this cover hold up in heavy rain?

Seams are sealed to shed water and keep cargo dry. Like any soft tonneau, don't expect desert-rated waterproofing — but it'll handle typical weather and highway spray without issue.