Once you are logged in, you can find your unique NLevel code on the profile side bar option marked 'Code'.
There, you will see a section of code that looks like this:
<script defer prop-key="ypxLoFDSLb7tec5SSEF8ASgIHfTsWvJZauP9g3" prop-id="ip81wg8pxf" src="https://nlevelsoftware.com/js/nlevel.js"></script>
To install this code, you need to copy everything and past into the code of your website, on every page you want to track