Installing Docker is quite specific for each hardware architecture and operating system. Here we'll be using Docker Engine for Debian on ARM64. This may seem like an arbitrary choice, but it is also what we would want to install to get Cardano running on the RaspberryPi 4.
The following assumes that you already have SSH access to a running server. In case you've just unboxed your RaspberryPi and are now wondering how to install a 64bit OS on it, have a look at the RaspberryPi 4 Setup.
Setup the Repository
First we need to setup access to the Docker package repository.