No, you don’t need to do anything else to the device. You need to log into the IDE portal (here:IDE Login, select your location/hub, go to the “My Devices” tab, select the motion sensor, scroll to the bottom and select edit, click the dropdown that says “type” and select the device type that matches the device handler you’ve installed (should be “Xiaomi Aqara Motion Sensor”), then click the update button at the bottom of the page.
This FAQ might be helpful: https://community.smartthings.com/t/faq-an-overview-of-using-custom-code-in-smartthings-smartthings-classic/16772