You need remote PC control with the following requirements:
- Free for non-commercial organization (INSTITUTION)
- Connection on a local network without Internet access (i.e. not like in TeamViewer)
At the moment all I've managed to find, it is Ultra VNC, but the program is very crude, the video is transmitted with a lag, typing on the keyboard very difficult. RDP is not suitable, it is necessary that the user saw my actions.