USMLE Step 1 studying was simple, after you are done with videos you just rely on First Aid and USMLE World QBank (UW for short). It's not the same for the USMLE Step 2 CK. Step 2 CK has no one source in order to fully understand the material. Unfortunately you have to make your notes your primary source. It's unfortunate that even to this day there is no one source that is a full comprehensible source.
NOTE: Basic Science concepts will be re-tested on USMLE Step 3. So save your Step 1 Notes.