2x turris Site2Site VPN

hi all
I’ve pcs of Turris (1x omnia + 1x “the blue one”), omnia is in HQ and “blue” in the branch. Both has static iP from ISP (different ISP). And I need to connect them via permanent VPN to allow users in branch to access files in HQ without establishing VPN by every user. Is there easy (for noobs) “how to” do that?

thanks Zdeněk

P.S. both devices are with the latest OS