Those products aren't brewed, they're manufactured. You can attempt to brew something from scratch but you'll probably have better results making it the same way the commercial producers do and add flavors & sweetener to an alcohol base. They are classified legally as "malt beverages" for tax purposes. An unhopped, squeaky clean "beer" is made and then ultra filtered to make a water-clear base. Various flavors, colors, and sweeteners are then added to produce the desired final beverage.
If you still want to make one like a beer I'd suggest searching "hard lemonade" recipes and sub tea for the lemon ingredients. There are several hard lemonade recipes that have positive feedback.