Direct answer
Objectives follow journal display order. Some depend on your choices; follow the active objective in the game.
Result
In White Orchard Geralt happened across a notice posted by a certain Odolan residing in the village. The man wanted someone to take out the monster who was haunting the area around an old well - and doing so required a professional. This was as typical of witcher work as they come, so Geralt decided to talk to the man.
Game homeThe Witcher 3: Wild Hunt RemasteredAll games