starting climbing from scratch

I have not been climbing for soo long that I am not sure if I remember how to even tie the rope,which would be dangerous,but, to start back means that I would need to start from scratch. I was atleast 6a or 5c in french grading system,but I think I would need to go back and start 3 or 4 routes. Maybe I would go bouldering more often to get back my strength as my arms often get weak. I would start next week.