Hi Just purchased a basic IMac with M1 chip.How do I connect peripherals eg external backup drive,charging lead etc- via USB ports,please

it have 2 usb3.1 and 2 usb4 ports

it's just that they have moved on to the newer connector called usb-c

rather than the old usb-a

you can get converters Amazon.com : usb-a to usb-c adapter

or get new cables for your peripherals

or you can get an usb hub with an usb-c cable

The best USB Type-C hubs in 2022 | Laptop Mag

I got the OWC Thunderbolt hub:

https://www.owcdigital.com/products/thunderbolt-3-dock-14-port

At work I have the Cal Digit for my MacBook Pro:

https://www.caldigit.com/ts3-plus/