How do you create a second account? I have a valid reason to get one!

Before any pikemen come out I'm not going to smurf, i have an archer strategy that I'm really good at but it inflates my elo and when i do literally anything else I'm pitted against opponents far better than me and it's hard to practice without getting demolished ten games in a row.

I'd like to have one account for my strategy then another for normal play. Do i have to buy the game twice to do this? Tried googling how to but didn't see any info. Thank you.