Eluna has an information center on Github. If you want more information about Eluna, you can go there (https://github.com/ElunaLuaEngine/Eluna) or read this thread (which will probably be quicker).
1. lua_scripts folder is the main folder you will put your scripts in
2. Some TrinityCore methods will be disabled until we get them working for both TC & MaNGOS
3. If your scripts do not work ingame, check the WorldServer console to see if your scripts couldn't load because of errors
4. If you're getting 'attempt to call global 'RegisterServerHook' <a nil value>' error, that's because 'RegisterServerHook' does not exist. You can view the correct Events/Hooks via Eluna's API
5. If any other things go wrong whilst using Eluna Lua Engine ©, create a thread in Eluna's support section