Human operations are currently not yet well supported in the Line Simulation mode.
You should be able to do some very basic things - see e.g. the attached video.
In this case I create regular (non TSB) Human walk operations for Jack and Jill.
Jill is set as the graphical representation for a new proximity sensor.
Jack is set as the object to check for proximity.
The proximity sensor is then used as a "transition condition" for Jills walk operation.
-> Jill will start walk whenenver Jack get close enough.
As far as I remember the main missing piece is support for "part apperanaces" in the human operations.
This is something that may be enhanced in a future version of process simulate.
We are interested to hear what kind of scenarios you would like to simulate with human in event based simulation.