To verify your site for Pinterest you have to supply a verification code to you site that the Pinterest servers will look for upon verifying your site. You do that in the Site Structure / Menu - Settings section. Scroll down and you will find the Pinterest area.
Click your name in the profile menu to go to your profile
Click the pencil icon on your profile
Add your website to the Website field
Click Verify Website
Click Verify with a meta tag
When you see the instructions for implementing the verification code you simply mark the the entire meta tag ( as illustrated in picture ) and copy it.
Go back to the BRIGHTBRIX® Web Producer Site Structure / Menu - Settings section as described in the beginning of this how-to and paste the entire meta tag into the field named Pinterest SiteVerification.