This is triggered when a Bonus Run is Batched Out (step 4).
Field Tags are used in the Messages section to drop in values from the database, such as the Rep's name, rank, or commission values. These are the Field Tags that are specific to Bonus.
We have just released your commission for this month's bonus payout.
You received ${BONUSPAYOUT} for the {BONUSDESCRIPTION} period.
Congratulations and spend your earnings wisely. You deserved it!