==== Required information ====
- iRedMail version (check /etc/iredmail-release): 0.9.6 MARIAdb edition
- Linux/BSD distribution name and version: xenial Ubuntu 16.04.2 LTS
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL (MARIAdb)
- Web server (Apache or Nginx): Nginx
- Manage mail accounts with iRedAdmin-Pro? - No
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

Simple NOOB question (I hope).  I have searched far and wide, but I cannot find an answer though it is probably sitting somewhere really obvious. 

I would like, for reasons which are not really important just now, to add a third webmail client but I cannot find where the web root directory is located so I can do this.  I have found the config files, but this is my first foray into Nginx (which I did not actually plan to do, I wanted Apache in anticipation of this extension but I obviously picked a wrong option somewhere, but I am happy to have a go).  Anyway, any help for where to read up would be greatly appreciated.