This guide is the counterpart to this help. It explains the concepts used in GnuCash and has a tutorial that takes you through using GnuCash to manage your accounts. It will appear if you choose Open the new user tutorial in the Welcome to GnuCash! menu.
To open this Guide manually go to Help -> Tutorial and Concepts Guide.
It is strongly recommended to read this guide if you are new to GnuCash or unfamiliar with accounting concepts.