How do I add a pop-up (non-inline) sign-up form to my website?

I am trying to use one of the new Signup Forms but the instructions are very confusing and incomplete. First it says the Universal Code should be placed once just before the tag. Then it actually say to place the code in the location of the website (widgets for example for Wordpress) where i want the form to show. Now, this means if I have 3 forms I have to install them 3 times ? I looked on youtube but all the videos I could find refer to the Inline form, not the other ones. Has anyone done this and can help ? Thank you