Welcome to the Tome Basic Set. Tome is a fantasy adventure roleplaying game played with dice, paper, and pencil. You can also play online with dice rollers and google docs and stuff like that. The book assumes that you have already played at least one other roleplaying game, or that someone you know has done so and is helping you learn. Perhaps a different fantasy game, a cyberpunk game, something with a horror theme, or even some other genre entirely. You can probably learn it all without any previous roleplaying experience, it just might be a little more confusing at first.
This is a very slimmed down version of the full Tome game. It is intended to focus on ease of introduction, allowing new players to get started playing without being overwhelmed by the normally vast complexity that is a full scale roleplaying game (particularly Tome).
Tome is a Fantasy Kitchen Sink, which means that it does not have a specific setting like some other games have. Each game of Tome has its own world with its own places and NPCs. Just about anything you can imagine in a fantasy story probably has a place somewhere within Tome. Any specific story can only include so much at once, so not every story will have everything, but you can always include your favorite stuff. The biggest limit is that players should all be the same level so that they don't outshine each other. If one player wants to be a farmer that reluctantly goes on their first adventure, and another wants to play Conan at the height of all his powers, the farmer character will probably feel pretty useless most of the time. That's no good.
Tome Basic focuses on the 1st, 2nd, and 3rd levels of the game, and somewhat more on dungeon delving than overland exploration. At these levels your characters are just starting to go from "normal" to "awesome", and most problems can be solved by hitting them until they're not a problem any more if you can't think of a better way.
The Tome Basic rules are compatible with the full Tome game, but many things such as class progressions and magic items are presented in a greatly simplified way. For example, the barbarians's Combat Movement ability is just "+5ft of movement with Move Actions", instead of "+5ft of movement for every 2 full levels". Similarly, magical weapons and armor are just +1 instead of "+1 per 3 levels (round up)". Once players are familiar with the game and moving into the higher levels, they can transition to the full formulas.
If you want overland exploration and levels 4 through 14, you should get the Tome Expert Set as soon as it's available (that was a great joke, trust me).