You can follow these steps to download and log in to the Reader App.
Firstly, you will need to download the Web Manuals application available in the App Store by typing Web Manuals Reader:
Once you have downloaded the App, choose the domain name to enter the correct site and click continue.
This would be the first part of the URL when login in from the browser.
Login with your login credentials
if you have previously logged in to your company’s site, you will be taken to the login view, where you log in with your Username and Password. Otherwise, you will be shown a login form where you enter the Domain name, which is unique for every customer. If you don’t know your company’s Domain, ask your system administrator.
If you'd like to learn more about the login settings, you can look at this article New Reader App Login Settings.