Once you've added a lead form into your demo, you can always make edits to it.
Editing Your Lead Form
Select the forms icon in the top right corner of the template. Then select the embedded form.
You'll then see all the details and can easily make edits to the form and its placement.
If the form is added to a specific screen, simply select a new screen from the drop-down.
Alternatively, you can always link the form directly from the guide's button.
Click on the call to action button within the guide, in the bottom right. Then click on the purple link icon to select your form from the drop down list.
Note, by linking the form directly from the guide, you will replace the original trigger.