There are two steps to researching any business idea.
The first is to find all the available research you can on your market, competition and customers by doing desktop research.
This may require hours of google searches, pounding the pavement in the area you want to launch your business and searching out media stories, ABS (statistics) research on that market.
The second step is called primary research which is research you commission yourself – including talking to customers, mystery shopping of competitors, concept testing and all sorts of other things.
The second step is usually more expensive, so start with desktop research and get a good handle on whether your business idea is a goer before you start on the primary research.