Pour your already prepared kombucha starter and the SCOBY into your glass Mason jar.
Brew the tea of your choice. Allow it to steep for at least 10 minutes. (It does not matter if it steeps for longer - that is fine. I have often walked away from my tea brewing for at least half an hour. You just want to make sure that it is still warm for the next step, so that the sugar will dissolve.)
Remove the tea bags (or loose leaves alternatively). Add the sugar. Stir with a wooden spoon until the sugar is dissolved into the tea. Allow the sweetened tea to come to room temperature. (This is very important. If you added the hot/warm sweetened tea to your glass jar containing your SCOBY and kombucha starter, the heat could cause your SCOBY to die.)
Once the sweetened tea is at room temperature, add it to your Mason jar containing the SCOBY and kombucha starter.
Place a coffee filter secured with a rubber band over the opening of your jar and place the jar in a darkened spot. (I keep mine in a cupboard. Some people keep it above the fridge. The main thing is, you want air circulation and to avoid direct sunlight.)
Allow to ferment for 7-14 days. (The length of fermentation depends on the temperature and personal taste. I find that because our house is warmer in the summer, the fermentation process takes less time - closer to the 7 day mark. However, in the winter when our house is much cooler, the fermentation period can take closer to 10-14 days. It also depends on how tart you like your kombucha. We prefer ours more on the tangy side, so we ferment it for longer. However, if you prefer your kombucha sweeter, simply ferment it for less time.)
When desired tartness is reached, strain your kombucha. Remember to leave the SCOBY and 1 cup of kombucha in your glass jar. This will be the starter for your next batch. The remaining kombucha can be refrigerated for drinking. (Optional - you can proceed with a second ferment at this time, if desired. For beginner purposes though, I would recommend stopping here until you get a handle on how the initial brewing process works.)
Repeat the process all over again for the next batch.