4.) Make sure you are logged into your Squarespace backend (you'll need to be subscribed to Squarespace's Business plan or higher to install Paid Members App).
5.) Click 'Settings' on the left:
6.) Scroll down and click on 'Advanced':
7.) Click on 'Code Injection':
8.) Paste the code into the 'HEADER' section then click 'Save' in the top left
9.) Now people can visit your website and get access to your members only content.
10.) To test this, you'll need to be on your live website (not the Squarespace editor).