it’s unclear whether you are trying to CREATE a new stack or USE and existing stack.
if you’re looking for info on how to use a specific stack, then i’d recommend looking at the website of the developer you obtained the stack from. each developer will be different. you may have to contact the developer directly to ask.
if you are looking to create a new stack from scratch, then you should look at http://api.yourhead.com – this is the documentation for the Stacks API.
there are also example stacks on the YourHead GitHub site, such as https://github.com/yourhead/ImageFunStack
and of course you can look to the many published stacks available as examples as guidance – however please don’t copy others work unless you have explicit permission to do so.