Yes, you need to do a regular allocation of the accrued vacation days. To do this, go to the "Manage Allocations" tab in the Accrual Plan and select "Time Off Type" from the drop-down menu. Then select the name of the employee and enter the number of days that have been accrued to their account. This will add these days to their balance, allowing them to take the time off.

I am also working on the set up of this module and I am using regular allocation to enter the initial balance. I don't think there is a field to enter each individual balance when you allocate the "Accrual" plan to the employee, where it would be more convenient. I was not able to edit the "Duration" field either, but after the accrual accumulation starts, the accumulated days show in "Duration" when you open the allocation for each employee. However, note that ONLY the accumulated days will show, without the initial balance of that time off type. If you find a way to do so, please share.