I don't exactly understand this card. What should i put near my units beside the invisibility token? How look this dummy token? Should i just put identical unit and move 2 of them same time? I can't find this in errata.

ZITARIX said:

It is explained at the end of the core rulebook (as a card errata):

Strategy Card “Go to Ground”: “Action Phase: Place up to two concealed squad markers on two friendly squads located in the same hex. You may not choose squads that are adjacent to enemy units.”

Hope it helps