OpenSUSE Network :: Install And Configure My Vnc Session ?

I need some help install and configure my vnc session at my Opensuse.

Right now I have installed nx client which works fine and is listening on port 5901.

I also want vnc to use when I want to check exactly what is going on my work's computer (when I go home)

I am reading the tutorial here:

And I would like to ask you the following

1.

Code:

For VNC client connection remember to open ports 5901-> in the firewall. (1 port/Xsession.) nxserver is listening to 5901. How to configure vnc to listen to 5902.

2. The guide also refers that

Code:

Here we "Prestart" vnc sessions for specific users, therefore no login screen is presented. This uses more resources as the VNC Session is running even when no client is connected to the session watching it. But there in lies it's advantage, "watching a session" and "using a session" are not the same thing! This method is very usefull for starting long running programs before going home. Once home you can re-connect to the session and see how things are going.