Access & Trunk modes over VSAT-iDirect

Gents,

Till now, we are working as data solution over VSAT media with default configuration of UN-tagged vlan [one vlan in additional to the default vlan per customer], what we should call this mode access or trunk? & if I make the vlan tagged, what the scenario will be?

If there are more than one vlan [in additional to the default vlan], the system forced me to be tagged for both of them, what would be the mode now?

I'm little bit confused