Need pointers to info to get started

Hi,

We (local government, few dozen users) currently use Teams for chat and calls. We also created a "Team" per department to share files (like holiday planning in Excel). Most of the data is still on network drives.

We have a commercial package for the public website and we also use that for our intranet (news updates, documentation, who-is-who, ...).

How do we get started with SharePoint? Which tool should we use for a specific use case? What to do in Teams and what in SharePoint? What info do we move where?

I don't know anything yet - help. Thx.