Assuming you're in the United States, google (*your state name*) Department of Insurance. Look for the official website (it will probably have .gov in the url) and there should be a link for becoming an agent that will go into the specifics. I'll do a general breakdown below:
To sell auto insurance you will need to be licensed in property and casualty. You'll have to do pre-licensing education, in some states you can do that at home, but others require you do actual class time. If you're new to the industry I recommend going to a real class so that if you have questions you can ask the instructor.
Before you do that though, ask yourself if you want to be an exclusive agent (meaning you work for only one carrier - State Farm and Allstate are both exclusive carriers) or if you want to be independent and sell a variety of companies. If you want to work from home, you may have to go independent since exclusive carriers usually have pretty strict requirements on the office you need to work out of. You'll need to check with the carriers you are thinking of representing and find out what their guidelines are and what their requirements are to keep your appointment. I think Progressive either has no minimum or a very low one, whereas other carriers want a commitment to write several hundred thousand dollars in premium with them a year, and if you don't hit it they will reject your appointment. Because of this, a lot of small agents have to use other brokers that are allowed to write with the other carriers; then that brokerage keeps part of the commissions with you getting the rest.
You'll need to get E&O (Errors and Omissions) insurance for your brokerage. This is similar to medial malpractice and helps protect you if you make a mistake that adversely affects one of your clients.
Finally, while more and more clients are comfortable doing everything over the phone (or online) and never seeing their agent in person, a sizable minority do like coming to the office. If you're working from home, I'm not sure how viable that is for you.
Several years experience as an agent.