As in topic. My group will fight Imperial Fists squad with terminator armours, and i want their Sergeant to have teleporter, but I have no idea how it should work.

Only tele i've seen was in RT, and don't quite liked it

Terminators mainly use them to teleport themselves aboard enemy ships or fortresses. They are pretty useless in combat because of being not very accurate and even space marines in terminator armour won't survive teleportation into someone else

Go read some space marine novels and you'll come across good description of them...

Basically you ideally want a teleport homing beacon (otherwise things can go horribly wrong), there's always a build up of ozone and burst of pressure and blinding light from the warp as the thing being teleported materializes. You could treat it as a Concussive/Flashbang effect using rules from the Black Crusade rule book.

Ideally have either scouts or regular marines sneaking about with a teleport homer. If the players can take and disable the beacon, then have 1 or 2 of the terminators arrive off target, late or injured. This gives the players a slight incentive to figure out what the beacon is (though any Legionnaire in the party should be able to deduce this).