Grab the latest build of Tor project from their download page for linux. I just did it and was 8.5.1.
Make sure you are in the same directory you downloaded the Tor project in to. In my case I downloaded it to ~/Downloads
Add the keyserver
gpg --keyserver pool.sks-keyservers.net --recv-keys 0x4E2C6E8793298290
Add the fingerprint