Once the threads are started, loosen the vice and reposition the hose assembly so that the socket is gripped in the jaws (again, wrapped in tape) and the fitting is accessible. Then the fitting must be tightened into the socket. Using standard wrenches on the fittings will likely mar their finish, so a set of special aluminum
AN wrenches is a good investment. Watch the reference mark made earlier to make sure the hose isn't being pushed out, rather than clamped. A slight bit of push is expected, though.