To change your Brawler's pins, click on the 'Brawlers' button in the main menu. You can also hover over your Brawlers and click on their names instead. Next, click on the 'Brawler' you want to change the pin for. On top of the Brawler, look for a pin labeled 'Player Pins.' Click on that box and select one of the available options. Next up is the 'Brawlers' section where you have two more boxes like those above called 'Pins.' Click on this area to select one of the available options from a list before heading into battle with your new repertoire of skills.