Download the correct package for your distribution of Linux from
https://teams.microsoft.com/downloads

You should be able to open the installer and it should install, if not you can run the following commands from a terminal

The install instructions are for Debian/Ubuntu/Linux Mint.

Install using dpkg

sudo dpkg -i Downloads/teams_1.2.00.32451_amd64.deb

Launch Teams by typing

teams

Or you can launch it from your Applications Menu

After Teams is installed and launched, sign in to your Microsoft account.