The tutorial system, known as Intro Bots, is a simplified version of the full game and covers the basics of the combat system without the more complicated aspects that come with playing multiplayer online battle arena games.
This means there are no trinkets or support items and no need to last-hit bots to earn gold — these are intricacies, says Riot, that will be taught elsewhere.
"With Intro Bots, we're aiming for a more approachable difficulty that gives all new players a manageable first experience. At the same time, we've designed many features to be dynamic based on a player's performance so the mode isn't a pushover — players quickly performing appropriate actions and behaving like an advanced player will see fewer helpful features and lightly amped-up difficulty. Novice players should be able to enjoy several games of Intro Bots and steadily learn the basics, while more advanced ones will quickly grasp the essentials and move on to greater challenges in other modes.
"Instead of broad, imprecise goals, we want to provide incremental steps towards power and success, which led directly to the personal quests feature in Intro Bots. Personal quests seek to provide useful, immediately relevant goals that can help new players get a feel for the rhythm of a typical League game, which includes unintuitive things like leaving the battle to go back to base. Since these quests are contextually triggered based on what a player is doing (or not doing), they're always relevant to his or her situation."
You can read the post in full at Riot's official blog right here.