mother plant

i understand the whole mother plant thing, what i dont get is hgow to and what way to prune it so it doesnt get out of control big???? and what is the easiset way to keep one a live??? pics of prunned mother plant would be much helpful

the point of a mother plant is to take clones from it, this keeps the growth in check, once it is too big, keep a couple clippings and flower the mother. It will stay alive as long as you take care of it, keep it on 18/6 or 20/4 or whatever and it will just sit and veg. I personally dont use a mother, i just take clippings from the bottom of every plant before sending into flower, so I always have them on the go.