After how many hours of drinking fluid or eating is milk made?

This is a wondreful forum...thanks to all those wondreful ppl out there for answering my ques.I always wonder abt the formation of milk.i simply want to know when does the body start making milk.Is it immdly after we eat or during we sleep or night or day.doesit have any pattern or does it start making milk after every feed or during the babys feed?becos i thght that way i can increase my milk supplyby acting accordingly.trust me i'm one mom(like all) who wants to give my baby best.i always keep wondering if hes getting enough with every feed.he seems content..but i admit he does not eat to my content..i want him to be chubby..his birh weight was 7 lbs now being 1.5 mths old he is 11lbs.and 23 inches.is he on right track...pls guide me.i love this fourum cos i get answers to all my quest in an understanding and niceway......thank u in advance...