to Push a new app to all phones with a tag you must first go to
https://business.apple.com/#main/accounts sign in than go to apps and books>search for said app add how many ever lins you need
save and than go to meraki
in the Hatch MDM go to System manager >Apps
Click on said app
check (Keep app upto date, Auto-install /auto-uninstall, Remove with MDM, Visiible in SSP
Group Type Manual
With ANY of the following tags
Add which tag to said app (for all phones Add Admin, Hatch-iPads,Hatch-iphones,Plex,recently-added)
Than save on the bottom should take up to 5 mins to push