Need major help with organic chem....

Third and final test arrived. 62. Yep. I'm a chem major too so I'm feeling mighty good right now.

70, 82, 62. Those are my 3 test scores in order of first test to last.

I don't even know how to study for this class apparently and it's fucking hilarious that everyone else has As and Bs and I'm struggling my ass off to get a c. Can someone please give me advice? I kinda want to get a B atleast............