What does "here goes nothing" mean? When can I use this phrase?

Native speaker’s answer
Rebecca
"Here goes nothing" means you're about to try something you haven't done before, and you're not sure what the outcome will be. You can say this when you're about to do something new, uncomfortable, or unpleasant. It's usually said just before you do that thing. Ex: I've never jumped out of a plane before. But, here goes nothing! Ex: Oh, no. I didn't study for this test. Here goes nothing. Ex: I heard Harry say "here goes nothing" right before he went on stage to sing. I hope he's not too nervous!