I would be prepared for them to be pretty frightened, but you should be able to work through it. When we got our puppy, the buns were very afraid and it didn’t help to introduce them to a few other dogs beforehand. We just did a lot of training. Mine understand the clicker, so it helped to click and give a treat every time they got closer to the dog, but it’s not necessary. Basically, I sat outside the pen with the dog, while my husband sat inside with treats for the rabbits. He just fed them lots of pellets and other high value treats, gradually moving closer to the dog. They were able to leave and hide if they wanted, but would get treats if they came back.
It took maybe a month, but now they are completely unafraid of the dog, even if he’s jumping around and barking and being crazy. They run right up to the pen and stick their noses through. They do not like other dogs though so they seem very specific about that. They thumped and ran away from my dog’s sister, who looks pretty much exactly like him (though of course she smells different).
Just take it slow and realize that some fear initially is totally normal (they are prey animals after all) but you can probably work through it in a couple weeks if you take it slow.