How do I trigger the DLC missions like Gangstas in Space and Trouble with the Clones?

I already beat the main story and nothing shows up

With the mobile where you trigger the other missions.

But nothing is in the phone menu just retrying the Final mission three way

Then you A) don't have the DLC or B) it didn't register properly.

The DLC missions show up pretty much from the start. Some later genkies are also added activities, but it also starts with a call.

If you got the Steam version you can check under "properties" in the DLC tab. It shows up as separate DLCs.

Sorry Xbox 360