Despite the fact that it is not a grain, quinoa cooks up much like rice. Use two cups of water to one cup of quinoa. Bring to a boil, reduce the heat then simmer about 15 minutes. Cooked quinoa still has a bit of tooth. Fluff it with a fork and you're done. You can also cook quinoa by adding it to soups and stews like you would rice, barley, pasta, etc. Some folks advise to rinse the quinoa prior to cooking in order to be sure to remove any bitter residue. I've rinsed and I've not rinsed and I honestly can't taste a difference.
In regard to the question of gluten, I'm not at all well-versed in gluten-free foods and I've no dietary restrictions on gluten, but everything I've read about quinoa seems to agree that it is considered "gluten free." The information I've read does indicate, however, that people could have gluten issues when the quinoa is processed into other products like flakes or pastas. This might be due more to contamination issues with the processing rather than the quinoa itself. Please do your research on the quinoa products you intend to eat if you are allergic to gluten.
I buy quinoa in bulk and I usually buy equal amounts of regular (white) and red. I love to combine them. I can't tell a difference in taste but I love the color combo. To make the pilaf pictured above, I cooked a mixed cup of red and white quinoa, fluffed with a fork and set aside. While the quinoa was cooking I quickly diced (pretty tiny) half a zucchini, half a carrot, and an onion. I also chopped 2 cloves of garlic and a handful of fresh parsely. In a large non-stick skillet I heated a tablespoon of olive oil over medium-high heat. When the oil was hot I added all of the ingredients to the pan except the parsely. I stirred and tossed and cooked this veggie mix for ten minutes or so. Seasoned with salt and pepper, a dash of cumin and a dash of homemade garam masala and I was finished. I added the cooked quinoa and the parsely to the skillet and tossed until everything was combined. Serve this hot or as a salad.