Boot from a USB or uSD card and use dd to copy the image. Use BIOS settings to change the boot order.

Example:
# dd if=/where/you/put/the/image.img of=/dev/mmcblk0 bs=1024k oflag=dsync status=progress

Helpful Link: How to get boot options for SDcard or USB drive to show up in BIOS

These images have a user 'atomicpi' with an assigned password 'atomicpi'.

It should be noted that 'bare' images are really devoid of quite a bit of useful stuff (samples, Python/Node.JS pin definition libraries, etc.).
They usually have only the low-level stuff. Pin definitions are present in /usr/lib/atomicpi.sh in all images and can be transformed into other languages as well, not just Python or JavaScript.

Some of the 'bare' images don't come with networking configured as DHCP client by default (looking at you Buster) so you might need to do e.g. "sudo dhclient" for that.

Information and Links:

FAQ: Click here
Homepage: Click here
Forums: Click here

[YouTube] Atomic Pi FIrst Look! $35 X86 Single Board Computer

[YouTube] The ATOMIC Pi Android x86 Test $35 X86 SBC

[Resource] ELECTROHAXZ.tk Atomic Pi Resource - Custom Images

[Forum] - Stability issues in default Ubuntu 18.04 image with video playback in VLC

[Forum] - German forum with some general information on setting up Atomic Pi

[Schematic] -Atomic Pi board schematics

[Schematic] -Small breakout board schematics

[Schematic] - Large breakout board schematics

[TOOL] - Rufus 3.6p - For creating bootable USB stick

[TOOL] - Lubuntu 19.04 LiveISO - md5 sum

Atomic Pi on Reddit

Atomic Pi Users Guide

What are the mating connectors for the CPU card?

Board outline in PDF format