OK, the way I understand it, Forissa conducts a ceremony (benediction check), then DrZ makes an pledges and oath (sacrament check). Default difficulty is Routine (2 steps required).
The Benediction is a sustained task with a 15 minute increment. Spending another 15 minutes adds 1D (although this is not necessary in this case as Forissa made the 2 steps) When the task is complete, Forissa DrZ gets an endowment.
So, DrZ needs to pledge an oath, (make a sacrement check: roll a number of D10 equal to Guarin's Divinity score, each result equal to or under his Benediction skill is a step. Two steps are needed).
Then Forissa(?) can choose an endowment. The endowment will last for the length of the 'quest'.
BTW. The rules suggest granting 1 freebie endowment to characters for each point of divinity they have. This is a DM discretion endowment, to be used to control the flow of the story.. Passionate prays to God by characters may also prompt me to throw one in.