how to conect main www folder with ftp?

Hello , i am new to CWP(also linux). I like GUI and settings its all fresh and easy to navigate.
I ve just finished(i hope  ) domain installation and all basic settings in cwp.

I am confused that i have created 2 users that related with my main domain.
When i login via ftp each one pointing to different physical locations than my main domain files which is located on "/usr/local/apache/htdocs". I thought that after i link accounts with the main domain , i am able to reach that folder(/usr/local/apache/htdocs) when connecting via ftp.

So my main question is how can i reach that location with ftp : "/usr/local/apache/htdocs" to upload my web files.I tried to connect with root account over ftp it says password is incorrect which i type correctly.

normally CWP sets websites under a user. so that mean. it makes /HOME/YOURUSERNAME/Public_html and the FTP should be pointed too /home/yourusername.

So before you add any domain. Add the username first and under that username you add the domain.
The main www folder you should not touch unless you know what you doing. if you delete that folder apache will not start. and simply make a folder with the same name will also not work. On my server he did not liked it. i needed to reinstall all. was faster then searching for the error. so if you really want to connect with ftp to that folder you can login with filezilla and use the ssh protocol and your ssh port. normally port 22 and your root and your password. or way easier use the advanced filemanager  in CWP admin. but it is always a bad idea to use root as ftp. you can upload the wrong things and later you get problems.