The orderId should be an identifier unique to your system. This can be used for de-duplication.
Revenue is a monetary value associated with the conversion. Currently the revenue value is currency agnostic.
Creating an In-app Conversion Goal in Perfect Audience
Once the event you want to count as a conversion has appeared in your account, you can create a conversion goal attached to it.
From your Dashboard, select Manage-> Create Conversion.
From the Create Conversion page, select the In-App tab, then give the conversion a name.
Select the event you want to associate to a conversion.
Enter a revenue value (or leave blank if you are passing revenue values to your account through your app.)
Decide if you want to count this conversion every time it occurs, once per unique OrderID, or one per unique user.
Click Create Conversion Goal when you're finished.
After the conversion creation all subsequent events that match the Purchase event will also be associated with the newly created conversion.