General

Because this doc will describe on how you get Alpine to boot from USB, you should prepare by doing:

Download a tar-file containing Alpine (e.g.

https://web.archive.org/web/20101206020622/http://dl-3.alpinelinux.org/alpine/v1.8/usbdrive/alpine-1.8.3-i386.tar.gz)

Make sure you have a program on you computer that can extract tar-files onto your USB (See also http://en.wikipedia.org/wiki/Tar_(file_format) )
Get a USB-mem with at least 400MB of free space

Note: In this document we use linux-commands in order to prepare our media.

Preparing the media

install syslinux (i.e sudo apt-get syslinux or emerge apt-get syslinux)
Copy MBR to the USB drive (assuming your USB drive is /dev/sda)

sudo dd if=/usr/lib/syslinux/mbr.bin of=/dev/sda

Run syslinux with your USB drive as parameter.

sudo syslinux /dev/sda1

Flag the partition bootable

fdisk /dev/sda
 a (Toggle's the bootable flag)
 1 (The partition you want to have the flag)
 w (Writing your changes to the disk)

Windows users: syslinux.exe and 'fdisk' is also available for Windows.

Unpacking

Unpack all the files to your usb drive using a tar-unpacker

Windows users: 7-zip and other software can be used on Windows to unpack tar-files.

Boot Alpine

Put your AlpineLinux-USB in a computer that can boot from USB.
Note: You might need to change boot-order in your BIOS-settings in order to boot from USB.

When your computer has booted you will get prompted for a username.
On a clean AlpineLinux you just enter root and no password and you will get logged on to your Alpine linux.

Alpine Linux has some special applications that helps you to use it in the way you want.
Some of the first scripts you are suggested to use is:

setup-alpine (Configures all basic things on your Alpine Linux)
setup-acf (was named setup-webconf before Alpine 1.9 beta 4) (Configures ACF (webconfiguration) so you can manage your box through https)

Note: Just type any of the above commands on your console and hit Enter to execute the script.

Other useful pages

Configure Networking
Setting up a SSH server (Using ssh is a good way to administer your box remotely)
Package Management (apk) (How to add/remove packages on your Alpine)
Init System (rc) (Configure a service to automatically boot at next reboot)
Alpine local backup (lbu) (Permanently store your modifications in case your box needs reboot)