An RPG (Role-Playing Game) is a game where the player of the game takes on a certain role, and has to accomplish certain tasks.
The tasks may be rather simple (Too much of this is not reccomended, however, as this would make for a rather short or dull RPG), such as delivering a note from one character to another. On the other hand, they may be somewhat difficult, such as having to purchase certain items (This may prove difficult for the player, as in the game, there may be many events where they lose Gold, and the item may be barely obtainable by the time they arrive, for example.), or defeating a certain number of foes. Again, this may prove to be difficult, as the enemy(ies) in question may be barely defeatable.
It is recommended to give the player hints on what to do in the games. For example, if they arrive in a church map, and no character has told them the relevancy of a church, something as obvious as a frequently encountered character may give the player a brief hint on what needs to be done. However, it should be at least somewhat clear, and not too vague, if the intention is to make the player have to guess a little, on what to do.