Need big help guys

Hi . so recently I updated my moto e to 5.1 ota . I unlocked the bootloader , I rooted it , I did factory reset , installed everything I need , bought Sony 16 gb SD card , Sony headphones and I am almost ready to go . now guys I need someone to tell me how exactly link2sd works, how to make partitions in SD to work . then tell me if but if really cm12.1 is better then ota 5.1 (not assuming low memory on ota as a con) and guide me thru kernel stuff why and why not , how to and which one . I only need to know these things so I can fully enjoy my lovely phone , play huge games and ofc not worry about memory msg. Hope someone will help me on these q.
Thanks in advance , sorry for my bad English and have a nice day :*