hello doctors just starting studing for the step 3 u world ,should I start with CCS or q bank first ,thank you for ur time

Hi it does not mater. you start reading book of your choice and then first time do uworld questions system wise and do ccs cases to be familiar with to software. once you finish systems then second time do random timed questions and keep practicing ccs cases.
I have recently taken the exam and found that on Day 1 you need to review First Aid step 1. There were many questions on basic sciences , statistics, ethics, patient physician relations, Drug mechanism of action, basic pathology concepts, Microbiology bugs characteristics, Clinical anatomy.
Day 2: more like management, diagnosis, prognosis, preventive medicine,

Hope this will help
Good Luck!