Direct answer
Objectives follow journal display order. Some depend on your choices; follow the active objective in the game.
Result
Geralt spent some time rutting around in the dank alleyways of Novigrad and at one point came upon the body of a mysterious man. A cursory inspection revealed that this unfortunate soul had been struck several times with a sharp object. Though he seemed to have managed to flee his attacker and hide in this alley, he had bled to death shortly thereafter. Geralt realized he could follow the trail of blood and find out who had done this to him - and why.
