How to install system on EMMC storage

I am having a hard time setting up my Radxa Zero 1. I have tried mingling around bunch of ROMs, but I just cannot get it to show up in my system as a USB storage. I also tried connecting to it through UART, but I only get a bunch of gibberish at a second I connect Radxa to power, and then nothing. Can someone walk me through the setup process, with explanation of what each ROM does? Thanks in advance!