You may feel like you have nothing to remember but you also might've forgotten it during the first few secodns of you waking up. Cling on to the memory if you find you have one. It's not gonna last long for a beginner dream recaller.

It might also be useful to write down stuff in the DJ when you don't remember anything

"Entry 1: Didn't remember anything

Entry 2: Didn't remember anything, but I feel like I just woke up from a sad dream"