tvz82 Follow the instructions from our own documentation. Aside from the link you shared violating Flarum trademark, hosting offsite tarballs aren't according to our community guidelines and the installation instructions (as you've noticed) aren't complete.
The migrate command will become available after following the installer from the web or the php flarum install command.
@KaiKimera please take down the github team flarum-download asap, it's a trademark violation and breaches our guidelines. This includes the website, team and repositories.
