On the Plugins page for WordPress, click Settings (Fig 1). 

Fig 1

Fill out the API key (Fig 2).

Fig 2

Click on the Forms tab and enter the basic settings for your Signup Form (Fig 3).

Fig 3

Choose whether or not to send a Confirmation Email. 

If you wish to do so, you can override the default version and add additional / edit exiting text/buttons (Fig 4).

Fig 4

While still on  the Forms tab, select the Pinpointe database in your account where the form will point to. You may also select one or more of your lists to display on the form, allowing the contact to select which lists they wish to be added to (Fig 5). 

Fig 5

Lastly, in the Forms section, you may select to display any custom field in the form that is available and activated on the database (Fig 6). When you're finished, make sure to click the Save Changes button in the lower-left. At the top of the WP-Admin page, the system will inform you with a horizontal popup when the setting have been saved. 

Fig 6 

You now have two options you can pick from on how to display the form on your site:

• Popup: As a pop-up on one or more primary sections of your site (Home page, Pages, Posts, Everywhere else)
• Form Display: A fixed display on Pages and/or Posts