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".

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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);