I will send you 200 grams of starter. This is how you use it.
Take the 200 grams, add 200 grams water and 200 grams wholewheat flour. Stir well. Take back 200 grams into a jar in the fridge. the jar needs to be at least twice the volume of the starter, as it foams up by that much in the first day or two. This is your starter for next time. It will keep for up to 3 weeks without "feeding".
Let the remaining 400 grams (sourdough bakers call this stage the "sponge") stand overnight at room temperature (minimum 5 hours, ideally 8) to allow the yeasts and bacteria to build up. It should look foamy at this point. Next morning, add 200 grams water (maybe a little more if you find the dough too stiff- depends on the flour), 400 grams flour and salt to taste ( I use a tsp per large loaf). This time you can use whole or white flour, according to choice, but if white, make sure it is unbleached. Knead as usual. This amount will fit a large loaf-tin. Takes around 3 to 4 hours to "prove", then into a hot oven just as for yeast bread.
I keep 600 grams of starter and make three at a time (three kilos of dough) as this fits the top shelf in my oven. I make "batch"-loaves side-by-side in a large roasting tin (quicker to grease!). If you want to enlarge your starter, just add more equal amounts of wholewheat flour and water. Always multiply the flour by (max) threefold and allow to stand for a minimum of 5 hours (8 is better) each time you enlarge the starter or sponge. Sourdough buffs call these intermediate stages "first sponge", "second sponge" etc. If you bake regularly it's more convenient to go from starter to "first sponge", then straight to dough. Of course if you can't bake for a significant time, you can minimise the size of your starter and have a friend "feed" it every couple of weeks- if they don't want to bake with it they can just throw away the surplus each time, or use it to make drop-scones (made like pancakes only thicker).