As for as "permits," you need to register your business with your county clerk, of course -- and you may need some type of health permit (check your state health department's web site for more information). For example, Texas requires you to have an initial Food Manufacturer License, and to obtain one for a home-based business, you have to show that any areas of your home where you prepare or store food to be sold are totally separated by closed doors from any living or sleeping areas of the house. Yet certain cities in Texas have made it illegal to prepare food for sale in a private residence period -- so check your county and city health department websites to be sure that you can do what you have in mind.
As for "how to start from low," I assume you mean keeping your costs down to being with. Start simple, making the things you make best. Don't buy large quantities of supplies and ingredients until you have regular customers and know you need large quantities. Resist the temptation to spend your initial profits (or worse yet, go into debt) buying fancier cookware, a new oven, custom-printed cake boxes, or anything like that. Be very tight with money. Initially, only spend it on things that guarantee you more customers. You can upgrade your kitchen, expand your product line, and dress up your image down the road.
As for advertising, several good ideas are already posted. You say that you "sure know how to make good desserts." If you have a community college with a continuing education program in your city, your "know how" could provide extra income and advertising. You could teach an evening class to adults on how to make great desserts. Your students would obviously be dessert-lovers, and while most might use your recipes to make dessert for their families, you'd be the one they call to order special desserts for important dinners or events.
You might also try contacting the hosts/producers of locally broadcast early morning television shows. In the next month or so, these shows will book dozens of local guests to talk about topics of interest related to the holidays. Come up with something unique -- like an authentic traditional or ethnic Christmas dessert, a "themed" creation that would appeal to their viewers, or something for a specific market segment (for example, I love rich desserts, but have two friends who are diabetic -- it's hard to find good desserts for them, so if I saw you on TV with one, I'd probably order ALL my holiday desserts from you).
Also, contact the various private and public charitable organizations in your area that serve children. They are now in the process of arranging holiday parties and such that will draw tons of volunteers and lots of news coverage. Providing dessert for such an event would put you and your product in front of many potential new customers -- plus it'd be something you could feel really good about.
I wish you the best!
