Lots of choices as you have lots of new growth in a cramped space. Consider transplanting it if it will be getting large and you have room elsewhere. That way, it can reach its estimated size at maturity without you having to prune often. The ideal thing would be to only have to prune dead wood that gets killed by winter. By the way, if you still have it, the plant label has the estimated size at maturity (width, height).

You have foliage coming from last year's stems. You also have new stems growing from the base/crown. Those are usually keepers.

If you see a stem that does not leaf out by mid to late May, you can prune it all the way down.

Stems that cross or that are bent and flop can also be cut all the way down.

If you want to let some sunlight into sections of the bush, you can cut some more branches there all the way down.

Stems that grow too much in relation to others of its own age, they make the plant look weird so some persons like to either cut them all the way down or cut them such that they all have the same size.

You could go on but just remember, hydrangeas usually do not need to be pruned so, if you can, do not worry too much about pruning it. I would be tempted to leave this one alone until late May and theeen evaluate my options.