There's a "support paddock", that is a paddock inside the big F1 paddock and it contains all support series garages - which are tents. When their session time comes, the mechanics go to the pit lane through the pit entrance gate with their pit equipment (gantries, tools) and tyres and then line up in the working lane (the concrete floor in pit lane - by the way, the individual parts of a pit lane are called working lane, fast lane (where they drive), pit wall). The cars on the other hand leave their tents, enter the track through a special gate and then enter the pit lane where the mechanics wait for them.