How do you use the thunder bolt port?

In 2011 Apple introduced Macs with Thunderbolt. At the time, it was a separate standard from USB. They combined both standards in the same port with 2016 and later Macs that included USB-C.

The cables look veritably identical except for the fact the thunderbolt cables have a symbol of a lightning bolt on the cable connector. From 2016 Until Magsafe 3 was created thunderbolt connectors were also used to power Apple's laptops. Some still use thunderbolt connectors with a power brick. If you have no magsafe, it is important to use a power pass through adapter such as:

https://www.siig.com/search/JU-DK0F11-S1

https://www.smklink.com/products/usb-c-multi-port-hub

to carry your Mac notebook power through to add power to any peripheral device as USB-C on many of those Macs is underpowered for many bus powered peripherals. An external AC power adapter on a USB-C hub can also be useful. Thunderbolt is used for displays and hard drives. Where USB-C and USB-3 are used for mice, keyboards, and printers as well as adapters to ethernet, audio, thumb drives, and budget hard drives.

Thunderbolt 1 & 2 from 2011 to 2015 were used for hard drives, target disk mode, and adapting to firewire for camcorders.

Thunderbolt 2 to Thunderbolt 2 is possible.

Thunderbolt 3-4/USB-C to thunderbolt 2 is possible

USB-C to USB 2 or USB-3 is possible on many USB hubs.

But thunderbolt 2 to USB-3 is not.

For charging and external device attachment.

Power charging via USB-C is possible only through an adapter such as this one if the device supports USB-C:

https://www.smklink.com/products/usb-c-multi-port-hub

which basically takes the Mac's USB-C power adapter and adds power to any USB device linked to it from the Mac's power adapter, or an AC powered hub, or a device that has its own power source.

Macs that have Magsafe or standard A/C power will power their connected devices as long as Energy Saver (closing the lid) has not been run. If it has, a restart may be necessary before the ports are fully powerful.

Otherwise the device will need its own source of power. Exceptions are keyboards and mice, cell phones and tablets. Which all should be able to be powered by the Mac.

To best answer your question, what is your computing goal for wanting to use the Thunderbolt port on your M2 MacBook Air?

As you already know, this laptop comes with 2 Thunderbolt / USB 4 ports. They can be used to connect to an external monitor or to a number of other Thunderbolt or USB devices.