User39 A different guide for every OS that's comprehensive?
That's a lot of work!
There is some specific flarum stuff at the moment - composer usage, php 5.5+, etc.
But it's mostly very similar to installing any other php based program like wordpress. The acronym LAMP is there because its a group of programs often used with php based programs (Linux, Apache, Mysql, Php)
In fact, the best guide won't be a single step by step but rather multiple guides focusing on different aspects of setting up a webserver to serve content. Search around and you will find many comprehensive guides to various parts of a webserver. Once that's done, a 5 minute guide to installing flarum would work well ?