How do I connect my key pad to my ipad

An Apple Magic Keyboard for iPad, or Apple Smart Keyboard, simply connect via the iPad’s smart connector when magnetically coupled; no additional setup is required.

If instead you have a wireless Bluetooth keyboard, you’ll need to pair the keyboard with the iPad - by following the keyboard manufacturer’s instructions.

https://www.imore.com/how-use-bluetooth-keyboard-iphone-and-ipad

Depending on whether it’s an Apple Keyboard, or third party…

iPad keyboards - Apple Support

https://www.cultofmac.com/568793/connect-external-keyboard-ipad/

Your keyboard should have come with instructions on how to connect. The link above also offers good advice. If you purchased one of the three keyboards mentioned in the link but still cannot connect, contact Apple Support listed at the bottom of the link. If you purchased an different brand, then please contact them.