Obamacare open enrollment: Here's everything you need to know

Amy Braun-Gross is counting the hours until October 1.

It's not her birthday nor her anniversary.

October 1 is the day that marks the first time ever she will be allowed to buy health insurance.

Like more than 48 million other Americans, the Wisconsin stay-at-home mom does not have insurance to pay for doctor bills if she gets sick. It's particularly disconcerting when she thinks about her husband, Chris, who runs a tree-cutting business. Being an arborist is physically demanding. He has fallen out of trees.

"You know something as simple as a sprained ankle, none of that is covered right now, none of it," Braun-Gross said. "To add the cost of that to the debt we already have, we'd basically be up a creek."

Braun-Gross and her husband have tried to get insurance before, but they don't qualify. They both work hard, and they're college educated. But because of some pre-existing conditions, including Braun-Gross' weight, insurance companies haven't wanted their business.

Obamacare will change all that. The law forbids insurance companies from rejecting people like Braun-Gross because of their pre-existing conditions. To make that affordable, though, one of the most controversial parts of the Affordable Care Act is about to go into effect.

By 2014 every American, with some very few exceptions, will have to have some form of health insurance or be fined. The idea is that more healthy people will buy insurance, and the money the insurance companies save on them will cover the costs of insuring the older and sicker people who will now be in the insurance system.

Employers will provide insurance for three out of every five Americans in 2014, according to the Congressional Budget Office. Another 12% get it through Medicaid or the Children's Health Insurance Program. For those Americans and for the Americans covered by Medicare, October 1 won't mean much.

 Foes Go All Out To Undermine Obamacare

But for people without insurance, October 1 will be the first time they will be able to shop for private insurance in health insurance marketplaces, also known as exchanges. Many will be eligible for government help to pay for those plans.

 Clinton asks Obama about Obamacare

With so many politicians fighting over this controversial legislation, the details about how to sign up may have gotten a little lost. So, here is what Braun-Gross and the other millions of Americans like her need to know when open enrollment starts on Tuesday:

The deadline

Open enrollment runs between October 1 and March 31. You don't have to sign up that first day. In fact, you may want to put off paying for it until December. Plans bought through the exchanges won't start until January 1.

December 14 is the cut-off date if you want your plan to start January 1. Open enrollment runs through March 31. If you sign up in January or February your coverage will start the following month.