If you have previously saved to a Microsoft Teams, Group or SharePoint site you will be able to choose that from your previous Sites - University of Wisconsin - River Falls locations when you choose Save As.
Issue
If you use the Add a Place option, you will encounter a loop where Microsoft does not direct you to the correct location to add a site.
Workaround (in Windows)
If you have not previously saved to a site, you will need to add it using this workaround. After doing this then you will see it in your frequent list.
- Go to the SharePoint site that you are attempting to save a file into (from the files option in Outlook, the group or the Microsoft team). A web browser is launched and you are taken to the associated SharePoint site.
- From the web browser, copy the URL from the browser's navigation bar. You will have a URL such as https://uwrf.sharepoint.com/sites/department/team/something/SitePages/Home.aspx
- Go to the Office 365 product and choose Save As and select browse (the same option you might use to save to the T: drive) and a Save As window opens
- At the top of the Save As window, click into the box that likely says This PC > Documents
- Paste in the URL that you copied from your web browser and modify it, removing the last two pieces and you will have something like: https://uwrf.sharepoint.com/sites/department/team/something/
- Press <Enter> on your keyboard and it will attempt to connect to that site and a list of libraries will appear
- Double click on the Documents library option
- You can now navigate into any existing folders and save your document. (You cannot create folders from here; you have to first do that on the web in step 1.)