Type .addarena name-of-your-arena-here example (.addarena B-Ramp)
Go to Arenas in the menu and select the arena you made, add Spawns and Bot Spawns to your arena
You need to create a Spawn Box for player spawns
You will need to set the Widest Swing for each bot spawns. Move into the Spawn Box and press the Set Widest Swing button
There are lots of customizations and features in the Bot Settings menu
You will repeat steps 2-6 for every arena you want to create
After you are finished creating arenas you use .savecrossfire name here example (.savecrossfire Caseys Mirage Playhouse)
This will save your Crossfire Set to your account, you can then use Publish Crossfire in the menu, you will then need to confirm it by typing .publishcrossfire in chat which will then make it public on the website where anyone can play your Crossfire set and subscribe to it