And I quote from Janes Manual itself..
USER FLAGS
A user flag is simply a name assigned to an occurrence you consider important to the mission. For example, if you
want a flight of MiG-29s to take off when a SAM site is destroyed, then the destruction of that particular SAM site
should be labeled as User Flag 1.
Then when assigning an action to the MiGs, you select the Action TAKE OFF and then select User Flag 1 from the
Flag drop-down menu. It’s just that simple.
NO NOTE: TE: User Flags start in the FALSE or OFF state. They can only be set to TRUE or ON.
Click EVENT.
Click ADD to add a Mission Event.
Select the type of Event – User Flags are usually Goal State Events since they tend to hinge on whether a goal
is destroyed, see Event Types, next page.
Complete the information specific to the type of event, see Event Types, next page.
Action – Set Up User Flag “Name”
Click ADD under Action.
Click SET FLAG.
Select a User Flag number
Set the operator to “=”.
Set the Value to “True”.
Click OK.
The User Flag name (User Flag 1, User Flag 2, etc.) you assigned needs an event or condition assigned to it.
Condition – Set Up Event Triggers User Flag
The drop-down menu lists the possible events, see Event Condition Types, p. 6-171. The Mission Goals are listed at the bottom.
Click ADD under Condition.
Click the checkmark on the Goal/Flag menu to display a list of all possible events.
Select the event that triggers the User Flag.