Oh my Mustafa, welcome to Binky Bunny, how tragic and yet what a kind person you are to take them in from the cold. There are many rabbit rescue organizations with great info, the link you were provided with is just one of many, and depending on where you live they can also get you in touch with rabbit savvy veterinarians and care info (Binky Bunny too!).
A few other organizations;
The House Rabbit Society
The Rabbit Haven
House Rabbit Network
Save A Bunny
House Rabbit Resource Network
The Bunny Bunch
Rabbit Welfare Association – UK
Rabbit Rehome – UK
Vancouver Rabbit Rescue & Advocacy – Canada
All of these wonderufl organizations provide plenty of info and Binky Bunny can also help you get started (These are all under BUNNY INFO at the top fo the page):
Diet
Veggie/Fruit list
Cool Habitats
Bunny Proofing
As for a cage, I too would suggest an X-Pen or NIC condo made with Neat Idea Cube, Organize-It cube panels found at Target, Walmart or even Bed Bath & Beyond. They are wire storage cubes and under the Cool Habitats section you can see the many designs by our members. A dog kennel also works well too, make sure you get a large one so you place shelves in it. As with any cage, you will not want wire flooring that will hurt their feet, so be sure to cover it with old towels, rag rugs found at a discount store like Walmart, Big Lots or IKEA. Be sure to purchase a litterbox large enough for them and bunny-safe litter like Yesterday’s News, Care Fresh or Aspen Supreme. Do not use pine or cedar shavings, they emit phenols that can damage the liver and/or kidneys, not to mention the dust that gets inhaled.
Buy a good quality pelleted food without all the junk in it like seeds and colorful bits. They actually do more harm than good. I would stick with a timothy based pellet. Minimum 18% fiber, Maximum 1-2% fat, protein 12-14% & maximum 1% calcium. American Pet Diner and Oxbow are excellent brands. Often your local rabbit rescue will have a store where you can buy these things and you can also help the shelter bunnies out too.
Hay is sold in pet stores but you may find that your rabbits will eat quite a lot of it. The usual kind fed to rabbits is called timothy hay. The alfalfa hay is high in calories and calcium so is usally given to very young rabbits. Oat hay and meadow hay are also good for an adult rabbit. If you find you are spending a lot on hay from your local pet store you can purchase a bale of hay from your local feed supply store. This works great if you have the storage for it. Otherwise your local bunny rescue may also sell flakes of hay as well. Binky Bunny has a great store where all sorts of goodies including hay is sold (U.S. only).
I am hoping that both of these rabbits are either the same sex or one or both of them is fixed, if not, you may find yourself contending with a liiter of kits. So, you just might want to book that appointment with the rabbit savvy vet sooner than later for peace of mind. How big are they?