If the h2o did not go underneath the carpet, you should be able to use a shop-vac to suck most of the water out. Then, towel dry all of the wet areas. After that, leave the windows down for a couple of days to let air dry. It would be best to let it dry in a garage, for obvious reasons.

But check to see if water made it underneath the carpet. The best way to do this is to remove some of the trim in the door opening and wedge your hand between the body of the car and the bottom of the carpet to see if it's wet. Because the carpet is rubber-backed and is normally water-proof, it will not ever dry unless you remove the carpet, which is big job.

When this happened to my BMW, I had to remove the seats and most of the interior trim to get the carpet up. Even then, I could not remove the carpet from the car; I had to clamp it up and let the foam dry for a few days.

If you do not dry the carpet completely, you will have a mold problem so bad that you will be strongly tempted to drive the car into a tree. You need to get it dry within a week to prevent this. I detailed cars in college and had to clean more than a few where the owner submerged their car while launching a boat. They invariably smelled of aquatic life despite prompt treatment. River water is much worse than rain water, but you get the idea.