Mosaico extension 2.4 beta installation?

We have installed the latest of the mosaico extension (2.4.1592820024).

Either entering the Mailings >> Mosaico templates area or Administer >> System status results in an error message

Unrecognized Angular module

Or via civiCRM log files

[name] => crmMailing
[civi.tag] => deprecated

Unrecognized Angular module

The readme for beta-3 mentions both a validation step and the various template versions and an upgrade to verify them?

I’ve looked in /civicrm/admin/mosaico?reset=1 and don’t see a verification or upgrade system? How do I install this extension and check that it is valid?