So look on the sugar scale part of the hydrometer and see the sugar ounces per gallon that reads on the same mark as 1.030. Simply look at the 1.030 mark and rotate the hydrometer around to the sugar per ounces scale and read what it says. You will need to add about 8 cups of sugar. Now most of the time your must wont read as high as my example here, so you will usually use 10 - 12 lbs of sugar for a 5 gallon batch of wine. Remember that the temp.
White wines can be a little higher acid than reds.
Draw off about a cup of your sweet must and place it in a sterile jar of some sort, and then sprinkle your yeast into the jar with the 1 cup of must. At this point your yeast is in the jar and getting started. I sometimes add just a pinch of Sulfur just to keep the must from oxidizing while the yeast gets going. Add your pectin enzyme and your grape tannin. Cover the must with lid and place air lock, or use a plastic sheet or something to cover with and leave in warm place.