How do I FaceTime and message through my iPad Air Wi-Fi model?

For FaceTime, see:

Use FaceTime with your iPhone or iPad

Messages:

Set up Messages on iPad

The iPad User Guide is a rich source of frequently overlooked information about your iPad and iPadOS. The full Guide is available both online using a web browser (such as Safari), or as an Apple Books download:

iPad User Guide - Apple Support

https://books.apple.com/book/id1567104892

The Tips App, installed by default on all new models of iPad, provides a brief introduction - and leads you to the User Guide. In case you missed it, here is a link to the Tips App:

https://apps.apple.com/gb/app/tips/id1069509450

Apple also has a huge YouTube Channel - containing videos and feature guidance:

https://www.youtube.com/user/Apple

Tap the links below.

Use FaceTime with your iPhone or iPad - Apple Support

Set up Messages on iPad - Apple Support

Best of Luck to You!