Using POST function in Smarty

Can someone explain to me the exact steps on how to use the post function in Smarty PHP? I have to be leaving something out somewhere, and I'm not sure what. I'm workingin CMSMadeSimple and I want to post a variable from one form to another, except the variable doesn't exist in the first form. What are the steps I need to take to do this?

Clarification: I am using a module in CMSMS called 开发者_如何转开发FormBuilder. This module is accessing info from Products, another module. Now, these fields are what I'm trying to access. For instance, I am trying to pass info from the first form to a field in the second form which should be selected, where the name is "cntnt01" and the value is "205".

To assign the variable where it will be available to the first form, you need to call $smarty->assign() in the PHP script that produces the first form:

// Assuming your Smarty object is $smarty
$smarty->assign('variablename', $variablename);