Ethereum on ARM is a custom Linux image (currently for Raspberry Pi 4) that runs Ethereum clients as a boot service and automatically turns the Raspberry Pi 4 into a full Ethereum 1.0 node or a Ethereum 2.0 node.
TL;DR: Flash your Raspberry Pi 4, plug in an ethernet cable, connect the SSD disk and power up the device to turn the Raspberry Pi 4 into a full Ethereum 1.0 node or an Ethereum 2.0 node (beacon chain / validator).
Visit our documentation page to learn how to install the image and manage the Ethereum clients: