One-Off Legacy Expenses
Gifts (PETs) and charitable donations are scheduled on the Expenses > Legacy screen.
Do not over think the semantics of the "Yearly" option. If entered as a one-off expense (see below), the gift/donation will occur only once. In most cases a one-off expense would be entered in an annual amount. Select Applied: Yearly to indicate that the amount entered is an annual one. To schedule the expense, use the small 'Time' panel, as shown below:
Also note that legacy expenses are in fact treated more like a contribution -- like those scheduled for savings and investments -- than an actual expense. Unlike other types of expenses (basics, leisure, luxury, and milestones), a shortfall will not be shown in the cash flow if a planned gift cannot be made due to insufficient funds.
Future gifts (PETs or CLTs) can also be scheduled by setting transfers to be made into an Other Trust. An Other Trust can be set as being a Bare Trust, in which case the transfer would be a PET, or set as a Discretionary Trust, in which case transfers would be treated as a CLT. Transfers too can be scheduled as a one-off (the default) or set to recur until a selected event.