I am looking to connect existing USB cables (printer, backup hard drive) to my new MacBookAir.

Ok, so let me explain things technically, then explain what adapters you can use.

MacBook Air, M1, 2020, has 2 USB-C ports, capable of Thunderbolt. What you describe as existing USB cables are described as USB-A.

You can try: USB-C to USB Adapter - Apple (UK)

You could also look into a multiport from the likes of Satechi, or a Thunderbolt dock from the likes of Caldigit.

One option: https://www.apple.com/shop/product/MJ1M2AM/A/usb-c-to-usb-adapter