iMac: How to connect M1 iMac to the network via ethernet cable?
Power Adapter with Ethernet
The 24-inch M1 iMac comes with a 143W power adapter. If your iMac has four ports, the included power adapter has built-in Ethernet. The 24-inch iMac with two ports can be configured with a 143W power adapter with or without built-in Ethernet at the time of purchase. ITS started deploying the new Apple M1 iMacs during the summer of 2021. They are setup differently than previous iMacs, and no longer have an ethernet port located on the back of the computer.
Connect the power adapter
Pass the power cable through the hole in the stand and connect it to the power connector on the back of your iMac. Plug the separate power cord into the power adapter, then connect it to an electrical outlet.
Connect to Ethernet
Plug an Ethernet cable from your router or modem into the Gigabit Ethernet on the power adapter. The power adapter cable doubles as an Ethernet cable, so you don’t need a separate Ethernet cable from the power adapter to your iMac.
More information about the Apple M1 iMac
To learn more about what came with your iMac, and configuring the Magic Keyboard and Magic Mouse, go to https://support.apple.com/guide/imac/whats-included-apd768124354/mac