Opening the back of a watch can be tricky, but it's easier if you use the right tools. For most watches, a case opener or a small screwdriver works best. Gently insert the tool into the groove on the case back and apply a bit of pressure to pop it open. What type of watch are you working with? I'm curious if you've tried this before, or is this a new adventure for you? Remember to be gentle to avoid scratching the watch!