There are many possibilities in this game. You can choose the story mode that opens the game slowly for you, but still you have to be a little bit ahead of the game, with new challenges arbitrarily on the map, the map is getting bigger and you do not have infinite with crew so you should think tactically.
You must constantly think how much crew you will need of the different kinds and how many vehicles are going to patrol where.
You can also choose just start out the hard way and start with open game where everything is open also the entire map, immediately after, you get a big try everywhere and then I chose story mode to learn the game from the bottom .
You can quickly take many hours to go with the game.
Enjoy.