Use old iMac as MacMini Display

How to make use of the iMac as display for MacMini but limited to only those before mid2014 model.
Video demonstrate how to connect and the process how the old feature target display mode.

[@Mkate108]

Which model Mac mini did you use?

[@CTBLiew]

Target Display mode is not available for newer Mac. Any mode before 2014 and earlier should be fine. Can’t remember which year is my MacMini. You may consider having Luna Display or Duet Display.