Depending on where you get it, some of that may already be done. For example, at our shelter, if we're not overfull we spay/neuter (female/male) the most adoptable cats at our own expense. They are usually dewormed at the shelter, too. You should, if at all possible, arrange to go by the vet's office on the way home to have a quick check for any problems. If you get the cat at a shelter, it may well have an upper respiratory infection (URI), which is extremely common there.
Depending on the age, the cat will need to have a few innoculations, such as rabies.
For first-time cat owners, I recommend a cat no younger than about 3 months. Tiny kittens are cute, but they're a lot of trouble if you're not used to them, and they can get very sick very quickly.
You will need a litter box that is size-appropriate. That is, if the cat is small, don't get one that is going to be hard to climb into.
You will need a food dish and a water bowl, both of glass or ceramic, not plastic.
There are lots of other hints around here, but please ask about anything you are unsure of.