Need to get to stock from My-ROM EMUI 2.3

Hi. Sometime ago I installed a custom ROM, but I want to go to stock, preferably the latest. I honestly do not understand what EMUI is or how I can recover. I tried it once and got in a bootloop. Could someone sketch out the path for me to take? I have no problems finding the required files or topics but really need the general steps for this process.

Many thanks.