Create a process in Workflow that starts with a HTTP Input task. Let’s say you call the action “PrintSelection”.
In that process, add a Create Web Content task that calls your Web Template. Specify your Web Context and use record ID 0 to instruct the system to generate a Template without any data.
This will return the web form to the client browser. Users can then fill it, and the “Submit” button on that form should point to another Workflow process (say, “ProcessSelection”), that also starts with an HTTP Input task and that actually handles the data provided by the user.