Once you have your sourdough starter you need to feed it so that you have enough starter to make your loaf of bread.
The simplest way I have found is to measure all of the starter sourdough, say it weighs 200g, you then add 200g of flour (wholemeal I use) and 200g water and stir it well, adding in lots of air, then put into a glass jar or plastic container (make sure the lid doesn't screw on as the starter ferments and builds up gases and these need to be able to escape, I use a moccona jar and the lid just pops up as needed) and leave on the bench until you see lots of bubbles in it like the picture below. It is then ready to cook with.
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To make 2 loaves of bread
800g bakers flour
Mix into a dough and then knead until smooth and elastic, the first few times it took me a long time, but the last time I set the timer for 20 mins and found this was plenty of time to knead.
Divide the dough in half, shape and put in loaf tins, cover with a tea towel and leave to rise between 4-12 hours depending on the temperature. I have been leaving mine to rise overnight, then baking in the morning.
Ready to go in the oven
Then bring the temperature down to 220 degrees and bake for another 20-25mins.
Cool and eat.
I then slice and freeze my loaves in freezer bags. I find it easy to get out a couple of slices as required.
When you aren't using your sourdough starter you can leave it in the fridge to hibernate until you are ready to use it again. I have also heard that you can freeze your starter as a safety in case anything goes wrong with your starter, but I haven't tried this yet.
This website here has so much information on making sourdough bread, that all your questions will be answered. There are also recipes for using excess sourdough starter to make pancakes and choc chip cookies, which I have made and can confirm are delicious!
Here are a couple of links to the benefits of eating Sourdough Bread
5 Reasons to make Sourdough your only bread
The Health Benefits of Sourdough bread