With assistance from Binarylane I was able to install a CHR.
Either purchase a new server, or to delete and re-use an existing
server go to “Change Plan”. In either case, you need to set operating
system to “BYO Operating System” (shown under Linux)
Go to Backups section, and select Upload
Our system doesnt understand what to do with the .zip file, you need
to provide the chr-6.35rc35.img contained within it. You can either select
“HTTP upload” and paste in an address with an img file, or you can extract
the .img file on your own PC and do local file upload.
Once it is uploaded, choose to restore the backup
Go to the server’s dashboard, you will see Microtik installer do its
thing and you can then login.