How do I revise OC???

I haven't revised OC, my fundamentals are intact, but I need to revise the whole OC, should I watch lectures or refer to my notes, my notes are 1.5 years old, revison after a very long time, please tell me a way that is time effective. I don't just want to passively read my notes. Idk if I can recall the lecture but I can understand my notes, but it's vast and time consuming.