How we can build our extension

Hi ,

I want to  know how we can  bulid our extention using intergration studio.
if i have some piece of code in dot net  for example have to validate 2 control's values ( like compretovalidate required field validation)
is this possible to make extension for this?  if yes please show me process how we can achive this. or how we can publish or use this in our espace.

please  explain me step by step 
Thanks for the response.