Setting up Microsoft Fabric - IT infrastructure

Hi user_280 
Thanks for using Fabric Community.

Here are the steps to tie a Capacity to a Workspace in Microsoft Fabric:

1) Head to the Fabric admin portal.

2) Check if you can see the capacity you have just made in capacity settings >> Fabric Capacity.
3) Next, head to Workspace settings, then to the “Premium” tab1.
4) Pick the Fabric capacity and set the right license capacity for it.
Please ensure that your Fabric capacity is properly set up and that you have the necessary permissions to make these changes.
https://learn.microsoft.com/en-us/fabric/enterprise/buy-subscription#azure-skus

Please refer to these links for more information:
Microsoft Fabric concepts - Microsoft Fabric | Microsoft Learn
Buy a Microsoft Fabric subscription - Microsoft Fabric | Microsoft Learn

Hope this helps. Please let me know if you have any further questions.