significances of open_form & Start_form (urgent)

hi all

1. what is difference btw OPEN_FORM & START_FORM? what r there significances?

2. What is the diff btw CLOSE_FORM & END_FORM?what r there significances?

3. out of these functional modules which r mandatory and which r optional & why?

plz give it answer.

i am hoping to get some good replies from u all genius there.

thanks & regards

sanjeev

Message was edited by: sanjeev singh