Replace a band on a fossil watch brand 2753 georgia bulldogs

Bands are held to the watch body by springpins. To disengage them, I use a fine blade knife, and pull one end of the pin down by causing the blade to bite into the metal of the pin, between the eye of the band and the watch body. This method will work when dealing with leather straps, perhaps not with a metal band, depending on how much clearance there is between the watch fork and the band's eye.
If there is no clearance, it may be necessary to destroy the springpin to get the band free. Replacement pins can be purchased at a watch repairer.
Replacing batteries: You need the back off. Some screw on, most press in. Press- ins can usually be released with a knife blade, or small leverage device if there is a specific release place on the rear cover. On odd occasions, it becomes necessary to "use a hammer and chisel". Not easy.
Screw- off backs need a tool to engage the slots on the rear. Sometimes can be done with a pair of long- nose pliers.
The backs often have a fine rubber sealing ring, for water resistance.This needs to be put back in place carefully.
The batteries are held in place by various means, spring tension, clamping etc. Sometimes a screw or two must be loosened to free the battery.
Really, it is all a job for the experienced.
I only do work on my own and other family member's watches. I have a range of tools I have made for these. I wouldn't risk doing outsiders' watches. I do bands and batteries, but leave it at that.