So I like shiny baubles but don’t know how they work, looking for some advice

The watch below, my wife has had since she was 5, clearly quartz, her parents at some time (in the last 35 years) opened the back and removed the battery

We want to bring it to life to give to our daughter, it might just be fitting a battery but I can’t see the type or where it goes or it could be a new movement

Not really worried about the cost