What kind of grapes do you have? And what is your growing zone?
I am in Saskatchewan and have grapes that are adapted for here. Grapes only grow on the older growth and mine had to establish themselves for a few years before I saw any amount of grapes. There is lots of advice and videos in the internet that shows how to prune grapes. I have valiant and another kind that I cant remember right now, they don't seem to require the aggressive pruning that some others need, or at least that's what I learned in the internet. Some of the pruning that I saw on the internet seemed a bit confusing to me, since my plants were far more overgrown than what I saw there. I have let mine grow quite a bit since I have the room for them, I will just prune them back for the height and width I am looking for and I will prune a bunch of the new growth during the season that gets out of hand. Last year I had enough to make a juice concentrate, and I have made jam, most of them came off the older plant that I have, I have 7 now, lol.
Hope this is of some help to you