let me tell u that it is quite difficult to explain the whole thing thru a post like this.. instead i can tell you to read about saytzeff's rule in the ncert chemistry text books which are available online free download. just search on google for ncert books and you can get them.. read the chapter on alkenes. it is written very well im sure u will have no roblems..

if you still have doubts then surely i will help in a better way.. but first u shud give it a try yourself.