Affiliate reference to put on the end of our URL for Affiliate Advanced Settings

While testing referral link, I created this brand new one:

Then, below the lines, it's "Affiliate Advanced Settings" which was described as "There are times when you would rather hide your affiliate link, or simply not have to bother remembering the affiliate reference to put on the end of our URL. If this is the case, then you can enter the main URL of the site you will be sending requests from below, and we will sort out the tricky bits for you. "

I'm confused if someone replaced "" to be" could work for nothing or earns tons of tons.

For running an affiliate program, I am a newbie. Can you help me with an example for Affiliate Advanced Settings to replaced ""?