Lost new iPad

You can only track your iPad if the Find My iPad option is enabled before the lost.

FYI: You cannot remotely switch it ON.

You also cannot track using Serial or IMEI number.

Read here => If your iPhone, iPad, or iPod touch is lost or stolen - Apple Support

Here is Apple’s advice for lost or stolen devices:

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 active, you would stand a good chance of locating it. 

However, if the feature was not activated prior to being misplaced - or the iPad has been inactive 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.

You cannot locate a missing iPad with an IMEI - but if your iPad has be stolen, the IMEI can be reported as stolen - preventing its use on any cellular network. To do so, you will need to contact the Cellular Carrier with whom you have arranged your cellular plan.