Hello Adam Kizis.
Thank you for posting this in the Microsoft Q&A Community.
From my understanding, you would like to know how to create a new Entra ID tenant and link the tenant to your Partner Center.
Kindly follow this link to see the steps on how to create a tenant.
https://learn.microsoft.com/en-us/entra/fundamentals/create-new-tenant
Once you are done creating the tenant, please follow this link below for step by step guide on how to link your tenant to your Partner Center
https://learn.microsoft.com/en-us/gaming/gdk/_content/gc/getstarted/overviews/set-up-organization
Let me know if further assistance is required.
Babafemi