PC:
* Download the Radmin / VNC client
* Make sure you will remember or write down the IP of the computer
* Make sure network is available and that there's no connection problems
* Make sure you've set the password (especially on VNC)
* Make sure that remote server daemon is started (start r_server in case with first radmin installation)
Mac:
It just works (well yeah you just have to put one checkbox in system preferences after first OS installatio...