Hi Gary (TBS),
Welcome to the Answers community.
In Microsoft Teams, by default, there is a General channel (which can't be deleted), and the files shared in this channel will be stored in the SharePoint site, in the Documents library, within the General folder.
Any files that you store in Documents in SharePoint site outside of General folder will not appear in Teams automatically unless you Add the cloud storage. For example, in the screenshot below, on the left is the image from Teams Files tab, there are some files which appear in General folder of the SharePoint library (screenshot on the right).
Outside General folder, there are some files which do not appear in Teams. If you want to make these files appear Teams, navigate to Files tab in Teams and click Add the cloud storage, select the desired site and the library.
For more information, please through Should I store my files in Microsoft Teams or in SharePoint? An understanding of behind the scenes
If you need any help, let me know. Have a nice day and stay safe😊
Regards,
Neha