You have found the Books section of the documentation. This is where longer-form documentation is kept. These documents are broken down into sections or chapters to make it easy for you to work through them at your own pace and keeping track of your progress. These documents were created by people just like you, with a passion for certain subjects.
Would you like to try your hand at writing an addition to this section? If so, That would be GREAT! Simply join the conversation on the Mattermost Documentation channel and we will help you on your way.