Fishmommy,
QT is to protect your existing display from introduction of disease, however it is really about adapting your new fish to your environment and getting them healthy so they can eat and become strong and survive.
Jawfish need a burrow to feel safe ... so you need to ensure that you have PVC tubes that mimic a burrow.
The best would be a tupperware container with sand and some pvc tubes buried at a angle much like their real homes. The pvc tubes are not full of sand ... they are open so the jawfish can enter. You can even do this with your display to "force" the initial home for them.
If you use a container of sand, make sure your new jawfish can find this. When introducing to the QT use a large glass and put the jawfish in this and then put this upside down over the burrow until the jawfish finds it.
Good luck and enjoy.
Cheer,
Bruce