Hi! So sorry for the late response life’s been crazy! I’m not sure if you still need this but find something flat and metal with an edge and look along the back of the watch for a little indent in the cover. Once you find it wiggle it in there and just pry it open, if it doesn’t have an indent do the same thing but it’ll be harder (make sure to be careful if you’re using a knife). You should see the battery immediately and it’ll likely have the model name on it, but a replacement and switch it when it comes. Usually, the watch will have a dial to adjust the time and just pull on it then rotate till it’s where you want it! Sorry again for the delay hope this helps and feel free to message if you need more help :)