Open any Browser and go to https://bigsurtech.hostedrmm.com
Login with your email address and the password that Big Sur gave you. This is specific to this portal only. You’re actual email password will not work here.
Once you have logged in, click on Computers on either the right or left, it will show you what desktops you have access to.
Once you click on the computers from above, one or more of your authorized desktops will appear, one per line item. Click on the desktop line item of the computer you will to remote into. You will then be connected to that desktop.