Your iPad cannot be traced or remotely managed using the device Serial Number. For future reference, here is Apple’s advice for lost or stolen devices:
Locate a device in Find My on iPad - Apple Support
If your iPhone, iPad or iPod touch is lost or stolen – Apple Support
Use the Find My app to locate a lost or stolen device – Apple Support
If the Find My iPad feature was enabled prior to it being “misplaced”, then if still active, you would stand a good chance of locating it. However, if the feature was not activated prior to being misplaced, has since been deactivated, or has been inactive and without a network connection for more than 24 hours, the last known location will not be available - and the opportunity to use technical means to recover the iPad have been lost.
Assuming that you still have access to your AppleID account (now also known as your Apple Account), you would be best advised to change your account Password:
Change your Apple Account password - Apple Support
If your iPad was a WiFi+Cellular model, with an active Cellular plan, ensure that you inform your Cellular Service Provider so that your plan can be suspended/cancelled and your IMEI blocked.