Hi guys, I am very interested in building a distro.
I also want to help the team to improve LibreElec.
I have some question and i hope someone help me 
1) How i can help you to find a bug and partecipate to github?
2) I have 2 raspberry with rasplex and LibreElec, it's possible to merge them? I need only live tv and plex, rasplex it's a plex with power and LE it's a Live tv powered
I try plexmbc but it's very slow.
3) Someone can show me how to buil custom distro 
Thank You
to 1)
install vanilla LibreELEC, probably one of the nightlies from here:
LibreELEC Alpha/Beta Preview Builds – LibreELEC
Test every possbile scenario and see if you find something that doesn't work as expected. Then report at the "Bugreport" subforum.
For github:
Get your own github account and fork libreelec and clone it to your machine. Build LibreELEC from source or use a nightly. After you have found some issues, try to fix them on your own by changing the specific code. Then compile LibreELEC and see if your changes really fixes the issue you found and that it doesn't harm any other section. If all went fine, do a pull request at LibreELEC and probably it will get merged. That's the best thing to provide help if you are able to code.
to 2)
probably with docker, but I'm not sure. I only know the plexbmc addon.
to 3)
I guess most of this might be found here: Linux From Scratch
I doubt there is a "step-by-step"-guide for building custom linux distros.
Both Rasplex (OpenPHT) and the official Plex distro for pi are now based on LE, we've been working together 
.. but LE assumes that there is only one mediacentre application running full-screen. In theory you could combine both apps into one image, but even if you did they would run discretely and you'd need to figure out the window management. You don't just add LiveTV to Plex or transcoding to Kodi - serious coding work is required.
NB: The rule for these things; if you need to ask how it's done you won't succeed. If you have the skills to succeed, our buildsystem already made sense to you and you're compiling something. It's a very arrogant statement (sorry) but experience also shows it's true.
Both Rasplex (OpenPHT) and the official Plex distro for pi are now based on LE, we've been working togetherNB: The rule for these things; if you need to ask how it's done you won't succeed. If you have the skills to succeed, our buildsystem already made sense to you and you're compiling something. It's a very arrogant statement (sorry) but experience also shows it's true.
Thank you for reply chewitt:) I don't have the skill for this I try because i like your work. In last year I use always openelec and I follow milhouse but I trust in libreelec and I want to help you.
Maybe I explain badly.
I want to learn how to build because I think I can help you on the work.
Sorry for my English I'm German
So biilding a complete Linux distro around a software is a very little bit different to compile a ready written code from source (which is also called 'to build something') ;). One could also say it's a damn complete different story :D...it isn't even a related genre 
Probably this helps you to compile from source:
The core OS is the same for both distributions, but the "application" (them: OpenPHT, us: Kodi) is different. AFAIK you cannot install Kodi addons in Plex.
