I have a Yashica 270 that has come from a family member who passes away. There is no manual and film inside. I shot the last few pictures remaining on the role. I don't see clearly how to get the film to rewind before I open it up. I don't want to blow it. How do I rewind? Looking at the back, there is one latch on the left side, one on the bottom. Which opens the back? Does the other do an electric drive rewind? Thanks! Joe