The question is a bit confusing, but I'll try and answer it as I understand it.
HTML pages don't process form data (unless you are using the GET form method, in which case you can extract values from the querystring), so you would have to point the form's 'action' attribute at a dynamic server page. Assuming (from your mention of it) that this is ASP, then you would set the action value like so:
<form method="post" action="myserverpage.asp">
<input name="firstname" type="text"/>
<input name="lastname" type="text"/>
Then you use a server-side script (e.g. in 'myserverpage.asp') to access the POSTed form values. What you do with them is up to you, but a simple example in classic ASP (as opposed to .Net) would be something like:
Which would render the two values back to the client's browser.
So, in summary, the HTML page's form POSTs (i.e. submits) the two values to the 'action' page, whereupon the ASP retrieves the POSTed values and responds by writing them out to the client.
If this isn't working, it means you haven't correctly installed ASP on IIS7 (it is off by default), follow these instructions for your OS:
(Basically, enable 'ASP' in control panel>turn features on/off>windows features)