SBA Loan is Government backed loan. If you are first time business buyer or starting a business, conventional loans ( direct through banks) are hard to get. Bank classifies you as inexperienced and highly risky candidate. So, to give opportunities to the new/virigin business buyer/owner, government backs the loan which is provided by the bank itself, not government, think of government as co-signer or guarantor in case you default on your payments.
As, any other loans, you will need to put business plan ( extensive one), goals, marketing, operational strategies, projections, products, vendors etc and research analysis and submit to the bank or SBA. Then, Bank will identify whether you qualify for conventional loans or it has to go through SBA. Usually, they want at-least 10-15% down-payment ( the more better). You have to believe in yourself and business and also convince both bank and SBA that you are determined and can run the business smoothly. Keep in mind, it is not a free money, somebody is risking that money for you.
The process is simple, although you have to do very good market research and write a extensive business plan ( Indian guy submitted 30 pages biz plan for 100 K loan to open indian grocery store in small town). Again, its your loan ( not SBA's), so before you decide to use this opportunity, decide whether the business you are burrowing loan is the right one. Once you mess this opportunity up, it will be really hard for you to get any other loans or even to start a business as American financial system works on lending.
Good luck mate !!!, Work hard and smart, you will make it anywhere.