The best gameplan in season 12 is to camp bot. ADC is such a prominent role in the current meta. Be aware of where your red buff is, if red buff is on the same side as botlane, you can place level 3 gank bot. Place 3 boxes to kill raptors and hit level 3 at around 2:15 to gank botlane right as the laners hit level 2.

Red buff is crucial to Shaco and is important to his ganking power, if bluebuff is botside you may want to start top. However, if your support is playing a champion like Nautilus or if your ADC is playing Jhin or Ashe it may still work out and even surprise the enemy botlane if you start blue and gank bot level 3.

If botlane is a low priority lane such as Ezreal Janna look to gank mid with level 3 and red buff then head toplane, or vice versa.

For box placement I suggest finding a youtube video to see all the different ways you can start off a game, and you should try it out in practice tool to make sure you got the hang of it.