Use Raspberry Pi Imager application to put Raspberry Pi OS onto an SD card. Before writing the SD card you can click a gear icon and select the options that will enable SSH and auto-join Wifi so that you can connect remotely.
Give it a username and password, this will be used to SSH into the Pi later on so make a note of it. After inserting the SD card, I booted the Pi, plugged into an HDMI monitor, keyboard and mouse.
Follow all the setup instructions from Copperhill here to set up the CAN HAT: