LPL - setting Boolean UserField to true

 I have a UserField (Boolean type) that I would like set to "true" or checked when the BenefitEnrollmentEvent is triggered. Presently it is initially set to "false" or unchecked.

I want to say something like:

"true when (BenefitEnrollmentEvent.EnrollmentType.LifeEvent)"

    UserFlag1

    UserFag2

Thanks