Homemade: Write a script using descriptive imagery to describe a sequence of events in a mental scenario. Record yourself calmly reading the script or memorize the script. Now relax yourself into a trance state while either listening to and visualizing the events in the script or by visualizing the events of the script in sequence from memory while in trance.
The Easy Way: Find a guided meditation or guided imagery video online. Listen to the guided imagery or guided meditation video and relax and enter trance state while visualizing the events of the guided imagery.