What is the best way to buy wine if you know nothing about it?
Don't be afraid to ask for help, or for an opinion. Most wine shops and wine sections of supermarkets and chain stores have someone familiar with the characteristics of the wines they sell.
Determine the price range you can afford. Ask the wine staff to give you some suggestions in your price range. It will help the staff tailor their suggestions if you can give them information about your preferences. Do you prefer red, white, or rosé? Do you like sweeter wines or drier wines? Do you like lighter wines or wines that are more full bodied? If you don’t know, they can suggest a wide range of wines to try so you can determine what you like. The best way to learn about wine is to taste it. There are no “right” or “wrong” wines.
Most reputable wine shops will have someone familiar with the characteristics of the wines they sell.