How can I set up a keyboard to my iPad A2602?

Let me help you with connecting a keyboard to your iPad, Settings > Bluetooth > Allow new connections (if pops up)

Then at the bottom select your keyboard name, and connect.

What keyboard did you buy among the ones listed here?:--> Keyboards - iPad Accessories - Apple

If it is an Apple Smart Keyboard, see this support page:--> Use Smart Keyboard Folio - Apple Support

If it is a 3rd party keyboard, please contact its manufacturer's support team and ask them.

Regards

Giulio

What kind of help exactly?

What type of keyboard is it?

Bluetooth?

Apple Magic keyboard?

something else?

Explain your issue in as much detail as possible, and someone may be able to help you.