Adding a Document Library link to a Teams Channel
Each Teams channel has a corresponding folder in the underlying Sharepoint Document Library. However, the Files link at the top of each Teams channel in Teams takes you only to that folder - not to the root of the Document Library.
Additionally, if it is not the first-named-channel (or default channel that used to be named General), you can't navigate up the folder tree.
A good option is a new link directly to the Document Library for each channel.
Below are the steps to do this:
1. Within the Teams channel, click the + button in the channel menu
3. Click on the Document Libraries option and then choose the appropriate Document Library (usually there will only be one)
4. Choose whether to post to the channel about it and then click Save
5. You now have a Documents link that will take you directly to the root of the Document Library for the team.
NOTE 1: Everyone in the team will be able to see this
NOTE 2: Unfortunately at this time, you cannot make this the default option when browsing to the team channel.