At the command prompt on the SUSE Multi-Linux Manager container host, as root, add the appropriate channels:

mgrctl exec -- mgr-sync add channel <channel_label_1>
mgrctl exec -- mgr-sync add channel <channel_label_2>
mgrctl exec -- mgr-sync add channel <channel_label_n>

Synchronization starts automatically. If you want to synchronize the channels manually, use:

mgrctl exec -- mgr-sync sync --with-children <channel_name>

Ensure the synchronization is complete before continuing.