Step 1 : Add you opponent on steam.

Step 2 : Invite him on the lobby and join the "Arms Race" mod. Start a "Arms Race" on whichever map.

Step 3 : The highest in the ranking after a full game wins. In case of tie, rematch.

Step 4 : Wash your hands 

Join discord to contact opponents and admins: https://discord.gg/jpeH62e