Most of websites have user communities and allow users to do some actions like posting comments if they are authenticated on this website. Often the performance of a web page can be quite different depending on that fact if this page was visited by authenticated user or anonymous one. So we need to test theese pages by both anonymous users and authenticated ones. How to add authentication is described below.
The steps are mostly similar to the steps of adding website search but have some small differencies.
First record HTTP/HTTPS requests going to authentication page with login/password form in your browser and submitting this form. You will get Authentication Form Page and Authentication Process transactions. Then you need to replace login and password parameters values by some variables like ${USER} and ${PASSWORD} on Authentication Process HTTP request settings.
After that you need to prepare the text file where each line contains username and password separated by some delimiter character, e.g., comma and add new CSV Data Set Config element like below.
And now all next HTTP requests will be performed by authenticated users.