Sometimes notable documents are uploaded to Teams and you need to find them.
In the Teams channel (e.g. PGST-Announcements), the simple thing is to click on the Documents tab at the top. Notice the bread-crumb. This will give you an idea of where it's being stored.
Go to your Teams channel. At the top there is a Search bar, type in a few letters or a word then hit Enter. You will get a few hits. Keeping the search simple will yield higher results.