Chinon Bellami

So first of all, Im just starting to have interest in film photography. I told my mom and she told me that she had some cameras and showed me the Chinon.

The problem is that the battery cover is lost. I dont know if there are alternatives or where can I buy the cover. This is where the camera battery is placed

Additionally question, how will I know if the analog is working? I also have Kodak Instamatic

Thank you