When I started brewing kombucha, I had a hard time distilling the instructions (which are everywhere) into the nuts and bolts. Here's the thing no one just spells out: for every 3 quarts of tea, use about 1 cup of sugar. The rest of it goes like this:
You need a container. Glass is best, metal and plastic are no good. Some people use ceramic, which is fine, though I like a transparent container so I can keep my brew on a high shelf and check on it from time to time. So I have a giant pickle jar.
For best results, you want the surface area to be wider than it is deep, but it doesn't matter that much. My pickle jar is much deeper than it is wide, but I don't usually fill it.
You need tea, green or black or oolong.
You need sugar, white or brown. No honey. 1 cup of sugar per 3 qts tea.
And you need a starter, aka a mother or a scoby.
It helps to have some brew from your last batch.
You need a piece of cloth. I used cheesecloth for a long time until a fruit fly epidemic in our compost made it's way to the cupboard where my kombucha was brewing. That was truly revolting. Now I use a clean piece of sheeting, which has a much tighter weave than cheesecloth.