Logging an Expense:
This screenshot shows how you log an expense. You type in a description, the cost and select who it applies to.
A screen from the group-summary page showing the 4 most recent expenses.
Logging a Settlement:
When you log a settlement, you choose who you are paying back, and how much you paid them, simple!
View Amount Owed:
This page tells you very concisely how much you owe each other. There are links to logging settlements if you need.