The Privy Code is automatically installed on your BigCommerce store when you install the app, but in case it's not working, you can try these steps to install manually.
If you haven't already, install the Privy app for BigCommerce. Once it's installed, your screen should look like this:
From this page click on the account dropdown on the upper right, then "Business Settings".
From the settings page, on the left portion of the screen there will be a “Privy Code” link. Click that link and you will be presented with the following screen:
Copy and paste the highlighted code to the clipboard.
In the BigCommerce menu, go to Settings > Design and click on "Edit HTML/CSS." Note: If you are using a default theme, you'll need to duplicate it first.
In the new window that opens, find Header.html on the left and click on it.
Paste the code on the bottom of the Header.html page, then click Save.
Privy is now installed on your BigCommerce store!