If you can’t find the indentation, scan the backside of your watch with a magnifying glass. Wear a pair of dust free latex gloves when replacing your battery.
It’s important to line up the back of the watch perfectly or you run the risk of damaging the watch’s internal parts. Some watches require a watch press to reattach the back to the watch.
Make sure to put the small screws in a safe place, like a ziplock bag, so that you don’t lose them.
There are also grip-balls that are made specifically to open the back of a screw off watch.
Screw off backs will have notches around the edges on the back of the watch. Snap offs will have a completely smooth back with a small cut or indentation where the back of the watch meet and watch meet. Swatches will have a slot on the back where you can fit a coin.
Wear a pair of dust free latex gloves when replacing your battery. Some watches won’t have anything covering up the battery. In this case, you can skip this step.