@David Soares Araujo Thank you for your query!!!
You should be able to get Activation Code to register the server in a similar way you would do for general SUSE sever as well.
You can refer to below documentation to understand the steps involved:
https://documentation.suse.com/sles/12-SP4/
https://documentation.suse.com/sles/12-SP4/html/SLES-all/art-sle-installquick.html
Same have been linked on our official docs here as well.
More info here as well.
Hope it helps!!!
Please "Accept as Answer" if it helped so it can help others in community looking for help on similar problem.