Capmonster is required to run some of our supported sites. If Capmonster is needed for a site it is mentioned in each of our site specific guide in sitelist.
You can add funds and check you remaining balance.
On your CapMonster dashboard you will find your API key which you need to copy and paste into the CapMonster section in the Carnage Bot settings.
Be sure to click save after pasting your API Key in Carnage and you are good to go.