That's usually how I set it up.
First, at the beginning of the session, the Watch Master assigns them their mission. I often let them pick their mission from two or three.
Then they attend the briefing with the Inquisitor Lord whose field agents have gathered intelligence and prepared dossiers and objectives so they're not dropping in blind. Usually there's some complications that they don't know about or don't have precise details on that will force the party to adapt on the mission. Sometimes, the situation is "our agents found something but weren't able to send us the details, meet up with them/find the dead drop to learn what they know," and that's when the party knows that **** really hit the fan.
Then they go to the master of the forge, and pick out their gear for the mission. This is by far the longest step, since this is also when the party plans how to approach it. They're also always afforded one 1 module for their Corvus Blackstar, and usually afforded one vehicle from the motor pool to take with if they need it.
Finally, they board their frigate that will take them to the mission and it begins [and begins to go wrong. These are PC's after all.]