I'm trying to unwrap a simple model so I could texture paint it. However I really don't understand the process of how to unwrap a model, especially the whole marking seams thing. I only use Project From View, which I think is not optimal when unwrapping certain models (especially complex ones). I've watched tutorials and can't seem to get the gist of UV unwrapping. I'm trying to unwrap the inside of the model, but it gives me weird shapes and sizes. Can anyone tell me how can I unwrap the inside of a model? or better yet, unwrap in general? Thank you!
Here is also the .blend file in case anyone wants to show pictures of properly unwrapping this model: