Our dentist recommends that brushing starts as soon as solid food is introduced.
There are two types of baby toothbrushes: those that you slip over a finger (better for when they don't have teeth, 'cause they're ideal for gums) and specially-sized infant toothbrushes with handles appropriately designed for small hands to grip. There's also infant toothpaste that's fluoride-free (when they aren't ready to rinse & spit, this is critical) that will help you clean their teeth. It usually comes in child-approved (at least in this house!) fruit flavors.
To brush her teeth, put a small amount on the brush and brush her teeth gently. It's okay if she spits out the toothpaste, it's okay if she swallows it (so long as it's fluoride-free); the important thing here is to (a) get her used to the routine and procedure and (b) clean what you can of her tooth and gum surfaces. If she bites the toothbrush, just remind her gently not to do that and keep working on it. She'll figure it out and hopefully will come to see it as a pleasant routine.
To add a bit of incentive for my two, we allowed them time to brush themselves, and then followed up with a bit of parental tooth-brushing backup. And since we're on well water here, we have a very tasty fluoride supplement that they get to take after brushing their teeth; acts as a little treat for them.
As for flossing, we use the little individual child flossers. Our dentist says that flossing is a good habit to get into but not essential until their teeth get pressed closer together, so the 5-yr-old is a regular flosser and the 2-yr-old is a recreational flosser. :)