Go to the location on your map. It will usually be in an out of the way place. Find the body accompanied by an audio log. Each location will be on the map provided you have got the ctOS tower nearby. After finding all the bodies, you will get a mission to take down the killer.
Bonus mission - Find the Suspected Victim, who will lead you to the Suspected Killer. Stay out of his line of sight and move in and take him down when it tells you to.
At the start of each you will need to find a person and hack their phone, then that will lead you to a access panel to pipe dream. Once in, scan the briefcase.
Bonus mission - Find and hack the pipe dream access panel. Then hack the phone to find out that he is being moved. Then chase and take out the indicated car, and kill the target.
Go to the burner phone locations and pick them up. Yup. He talks a lot.
Go to the location and follow the data trail to the access panel which unlocks the door. Inside is the weapons crate which can also be looted.
Bonus mission - Go to the location and take out the fixers there. After you clear, there are two more waves that will come. Save your explosives for the Enforcers and Elites at the end. The catwalk is mesh, so you can still be shot from underneath if you choose to hide there. In one of the corners, there is stairs up to a building which doesn't have the mesh to give you some better cover. Just be aware of the propane tanks stacked there if you are going to be fighting up there or using explosives. Found that out the hard way. Take them out early if that will make you feel safer.
Locations are shown in the videos. For each one, you will need to find the QR code on the buildings. Using perspective tricks and camera hacking, you will need to line up the QR code to be scanned.
Bonus mission - Go to the location and complete the pipe dream hack in the access panel.