Here's how I have been brewing kombucha since the 80s...
Bring about a gallon of water to a rolling boil. Add a proud 1½ cups of sugar, and continue boiling until the sugar is dissolved. Don't boil longer than necessary, as this depletes the oxygen in the water. Add a dozen tea bags and steep for 30 minutes. Remove the tea bags and let the sweetened tea cool to room temperature. Pour the tea into a large glass or ceramic crock and add at least a cup of brewed kombucha, plus a pellicle that you will have already obtained - either from a KT brewer or from past brewing. Cover with a clean cloth and secured it with a rubber band or string. Set the crock in a cabinet or other warm spot where it won't be disturbed. In about ten days you'll have a gallon of kombucha tea, ready to be drunk or bottled for secondary fermentation. If you want, you can add bits of fruit or ginger or herbs to the bottles. Don't put additives in the primary fermentation, however.
These instructions aren't exact, they're just guidelines. You can experiment with different kinds of tea - just make sure it's tea and not herbal tea. A dozen tea bags to a gallon is a good rule of thumb, but it's not cast in bronze. Both green and black tea will make good KT, and of course you can blend them. You can also use some of the exotic teas like kukicha or pu'ehr. Cheap white sugar works well, but you can use turbinado or even honey or molasses. Don't use non-sugar sweeteners like stevia, because it's the sugar that is the food for the SCOBY or pellicle - the colony of organisms that converts the tea to kombucha.
Once you have the tea in bottles, you can add things like fruits or herbs if you like. I'd get familiar with brewing straight KT first, however. When you add fruit, you are adding more sugar, which will reactivate the yeasts and can result in explosive carbonation. Aging the bottled KT will result in some amazing flavors as well. I've aged KT for up to 2 years although I think as a health beverage, it's better to drink it fairly fresh. Swing-top beer bottles work best, but you can use the polycarbonate bottles that designer water and some juices are packaged in.
Brewing your own KT is simple and doesn't require a lot of specialized equipment. It's healthy and refreshing, and helps to detox the body. It also adds important probiotics to your system.