How to Copy Over Query String Variables (GET variables) to the Variation URL of a Split URL Experiment?

Many times you would like to set up a Split URL experiment on a landing page that gets traffic from different sources. When those sources are mentioned in the landing page URL via query string variables (aka the landing page URL is "tagged") you might want to get those variables ("tags") carried over to the variation URL where the visitor is gonna be redirected.

We got this covered by simply selecting one checkbox as shown in the below screenshot: 

When that checkbox is selected  the Original and Variation(s) URL(s) get slightly altered with a so called "regular expression" that will do the copy of the variables. If you do not know what a regular expression is, do not worry, just click the checkbox and you are done. More advanced users can use the regular expression functionality to setup pretty advanced use cases of Split URL tests.