You don't.
If this is a secondhand, used device that was purchased, either attempt to return the device and get your money back OR just properly recycle this device.
No one here can help you. Apple WILL NOT help you.
Sorry.
Advice for the future.
If you purchase any iPad used/second hand, online, or even in-person, make sure this iPad does NOT have user activation lock and has been properly reset for sale.
A properly reset for sale iPad should initially power up to an animated, multi-language “Welcome” screen.
DO NOT take the iPad seller's word that this iPad is user activation lock free,
We have seen plenty of used iOS device purchasers get scammed.
User Activation Lock can never be bypasss, circumvented or worked around IF there is no correct previous/original user information to be able to do so.
Apple doesn't get involved with ANY user activation locked, used/second-hand devices, either.
So, buyer beware.
If purchasing a used device in-person, power the iPad ON
If the iPad DOES NOT display the initial animated, multi-language “Welcome” screen, then pass on purchasing this iPad.
If the iPad powers up to any other screen, then forget purchasing this iPad.
You cannot trust that the seller actually has the correct needed info to properly reset the iPad back to factory settings right then and there before the actual purchase and exchange of money for the iPad, in question.
Pass on the device.
If you are purchasing this used iPad online ask the seller to provide multiple images, either online or be sent to you via email, showing this animated, multi-language “Welcome” screen of the interested in purchasing iPad model.
Even better, ask for a short video be sent to you showing this animated, multi-language “Welcome” screen, in action and in its entirety, posted to the online ad or emailed to you.
If the online iPad seller refuses any of these requests, pass on the iPad. DO NOT buy.