javascript if statement to show only certain content

I have created a site from multiple html files.

In each of these html files, there is some text content.

The content is meant as a Userguide for 2 different stakeholders:

1. Manager
2. Admin Staff

I would like to seek advice on how to group HTML Text Content such that I could hide certain contents when I click on 'Manager' (and vice versa) on the navigation bar using JavaScript.

Could someone please provide the HTML code as well as JS code? Thank you very much.