Beginner prep help

i seriously wanna start my preparation now idk if its the right time or too late. please help me how to start the prep and drop some best courses or channels in youtube that are helpful not just helpful but really helpful at understanding concepts and everything better in this given period of time. i am new to this and dont even know the books or sources. but i want to be serious with it. i could give atleast 4 or 5 hours everyday