First you have to be in the proper unit.
If you come to CFJSR you may, once you are qualified, end up in one of the DART positions. You have a better chance on getting onto the Theatre Activation Team (TAT) as a new Sig Op if you end up in 1 Sqn. If you end up in 3 Sqn, you'll probably end up on a sustainment mission upon completion of your NCCIS Op Crse.
I have been in the Regt for 7 years and have never held a DART position as there are not many to go around.