So to fire up the drive, you heat up the Argosium plasma, tungsten starts to be converted, once you go over a specific negative mass value, a warp bubble is created around the ship. Now, there’s another Heavy Matter element which is key here - Salirium. Salirium is an element that a) attracts Argosium very strongly b) neutralises warp bubbles when they pass through it. When the warp bubble activates, all outside forces disappear - except for the attractive force of the most attractive source of Argosium (which could be several light years away), starting to pull the ship in that direction.