Since this isn’t a traditional visual novel, you cannot just cruise through the game by reading. None of the dialog options that you choose will affect this. There aren’t any special requisites to obtaining this ending all you have to do is reach the end of the game. This is the ending that most players will receive on their first playthrough. The game has three actual endings: a bad ending, a best ending, and an alternate special ending.
You may see the ‘End’ screen a number of times throughout your playthrough, but some of these aren’t endings at all, but more like checkpoints. This being the case, the amount of actual endings to the game are different to what the game lets on. Doki Doki Literature Club is not a traditional visual novel.