Q: Cellular data

Which instructions? What do the instructions say, exactly?

Does your iPad have cellular connectivity? Have you installed the SIM?

The 'cellular data' option may be labelled as 'mobile data' depending what country you are in.

This would be listed under Settings>Cellular Data at the top/left of the screen.

See: http://support.apple.com/kb/HT4157

If you do NOT see it,

Do you in fact have a model that supports Wi-Fi AND Cellular? Look on the back of the device for a model number..."Model xxxxx" (xxxxx being a series of letters & numbers) and post that here so we can check if it is indeed a Wi-Fi/cellular model.

Here is Apple's iPad identity page (identify your model by the model number mentioned above here):

http://support.apple.com/kb/HT5452