So I don't forget: In this example, the 2019-09-26-raspbian-buster-lite distribution will be installed.
This is for a Linux system. It should work on MacOS. I don't know about Windows.
Except for the dd command, all the commands can be run as a normal user.
Find out what disks are attached to the computer:
Insert SD card or USB stick
Find out the name of the new device:
Note the name of the device. Could be /dev/sdb or sdc or /dev/mmcblk0.
cd into the directory where the iso is.
Here be Dragons, make sure the "of=" device is correct!. Run the dd command to copy the image onto the device:
sudo dd bs=4M if=2019-09-26-raspbian-buster-lite.img of=/dev/sdc conv=fsync status=progress
After it is done. mount boot partition of the device.
cd to the partition
Enable ssh ability by adding an empty file called "ssh" to the boot partition.
Unmount (or eject) the SD card/USB stick.
Run nmap to see what is currently on the network. (ie: nmap -sP 192.168.0.0/24)
Insert it into the Raspberry Pi and turn it on.
Run nmap again to see whats new.
ssh into the RPI using email@example.com that you got from nmap.