Massed Entry allows you to give any competitor a performance or comparative placing in an event (eg 100m) without regard to their gender or age. It works in conjunction with a Program of Events.
For example, if 100m trial results are being collected under Massed Entry you would have a program of events with 100m events for different ages and gender.
Processing the massed results sorts them on the basis of the events in the program. At any point you may process massed results into those events and repeat it any number of times.

Option 1
Sorts the competitors by Age/Gender and puts the best as competitors into the relevant event(s) on the program.
Option 2
Adds competitors but goes a step further and pretends the event was actually run with those performances and processes the events, generating Team and Individual Scores