During the Cuprino Needed job, talk to Jackie to start this job. Head out in the Wasteland and follow your mini-map. Enter Mutant Bash when you reach your destination and talk to JK Stiles to start Mutant Bash TV. After you complete that, head back to Jackie. After you talk to Jackie, head over to Slim to start the event. Don't forget to use the Mutant Bash Weapon with LB if you're not in first.