Cant turn on wifi and it aint picking up the simcard in iPad Air 2

Welcome to the Apple Support Communities!

I understand you purchased an iPad Air with Cellular but have not used the Wi-Fi or cellular data features with it.

I have never managed to turn on wifi or use a SIM card

Do you mean you have tried to connect to a Wi-Fi network but have been unsuccessful? If so, try these steps:
If your iPhone, iPad, or iPod touch won’t connect to a Wi-Fi network
For your cellular data, have you purchased a plan and got a SIM card from your wireless carrier?
Set up cellular data service on your Wi-Fi + Cellular model iPad
Please reply to this thread with any additional information that you can about your network issues.
Take care.