There are usually two main reasons why your granola didn't clump together: 1) You didn't use enough oil: It is important to use a binding ingredient like coconut oil for this low fat granola recipe! Skipping this ingredient or using too little may result in granola that doesn't clump together properly. You will have a more crumbly texture rather than clusters. 2) You didn't press down the granola into the baking sheet completely and / or you stirred your granola instead of gently flipping it with a spatula towards the end of baking. Make sure to press the granola down into the baking sheet, and when you flip it in the last 5 minutes of baking, use a spatula and gently flip it in sections so that it doesn't completely break apart.