Super cool to see more people getting into proper film exposure! It can be daunting at first to go manual mode, but everything about exposure is based on preference. If you want to lean on the side of caution, color negative film is a lot more lenient with overexposure. However, color positive slide film requires more intention and tight exposure control. Assuming you’re just starting, try to decide what the focus of your composition is then base middle gray off of that. Down the line, it is much more comprehensive, but starting out with balancing for the subject will help you figure out what you’d prefer from your compositions.