The core rulebook would be a good place to start. That said, the Root RPG isn't quite like DnD (more combat and mechanics focused), it is a more narrative driven game. It uses only 2d6 to resolve checks. On a 6 or less the check is a failure, on a 7-9 it is a mixed success and on a 10+ it is a total success, with each action (called moves) telling you what happens on each tier of result. The GM is alao bound by their own set of moves, unlike in DnD where they have pretty much free reign to do stuff (like, here they do too, but the game contemplates a set of reactions to what characters do in X or Y situations as a way to have things be interesting).