This summary is not the rule. The rule text controls.
If you already have a license from the clerk of the Nevada Supreme Court that allows you to practice law, you can bring that license to a district court. The district court can then add your name to its own official list of attorneys who are allowed to practice there.
This rule basically lets district courts recognize the license you already earned through the Supreme Court process. You don't have to go through a separate approval process at the district court level. You just need to show your license, and the court can put your name on its roll of approved attorneys.
This matters because being on a district court's roll of attorneys is often what allows you to actually file cases and appear before that specific court. So this rule creates a simple way to move from having a state license to being recognized as a practicing attorney in a particular district court.