I bought gluten-free lasagna noodles, but I'm at a loss for how they want me to fold them. They are hard pasta noodles. Do I whisk a whole egg up to brush them? Just egg whites? Just egg yolks? Am I supposed to par-boil them to soften them up? Dip them in water first? Any ideas are helpful.
It definitely seems like you were supposed to purchase fresh Lasagna noodles, as Elenna123 said in a comment. If the noodles are hard, they're not fresh. Fresh noodles would be pliable enough for you to fold them like dumplings, for example.
If you really wanted to make use of the dry lasagna you purchased, you could attempt to cook them (follow the instructions on the box) and then after a small amount of drying (maybe about 15 minutes in an oven at 200-250, if I had to guess?) attempt to prepare them using the egg brush and folding them. You would normally whisk the eggs and brush that on the edges, like you expected.
Hope this is helpful, but really, my best suggestion for what to do with the dry noodles is simply to make some normal pasta. Lasagna is pretty tasty, after all. :)