Question About Sanding

Honestly, I wasn't sure of the next step. If I was supposed to put primer or rust protectant or wash it with a degreaser. I am fed up with the shed for the day. And I really need to sit down and plan out the cabinet. Do I put the primer before fixing the holes I am just not sure what order things go in. After the primer, so I sand again? Is this to fill in any scratches and such? And then do I prime again after that? When does the wet sanding come in? Sorry about all the questions.

Joanne