First open minecraft launcher in corner u should see somthing that says profile (your name)

Second click new profile and look a little down and u should see somthing that says Enable to go into beta and one under it saying enable to go into alpha it will warn u if click it this may crash but u should be ok u click ok

Last u click save and u press play and u can be in alpha or beta if u did it correct

Bye guys i hoped u liked my tutorial