A clear presentation of Sources and Uses (or Applications) of funds is critical for any transaction financial model, and in particular in a project finance transaction.
Sometimes this calculation is over-complicated with a large number of off-sheet links and complex lookups. Due to the importance of the Sources and Uses it is even more important than in other sections of the financial model to keep these calculations simple to avoid errors.
What is the link between a line summary and Sources and Uses of funds?
If the cashflow waterfall has been presented in the right way then you should be able to generate you output table of sources and uses of funds by simply calculating the line summaries.
As illustrated in the screenshot the Sources of funds are calculated as the line summaries of the relevant cashflow lines in the financial model. Exactly the same approach would apply to calculate the uses of the funds.