Development of Excel/Google Sheet to help predict date for issuing new payment

We have a requirement which is as follows: We have an excel project that should be completed in three phases, this excel/google sheet will complement or maybe in the future even replace an existing “cash forecast and daily sales” that we have. The intention is to have a new sheet that will help in predicting the date for issuing new payments based on pre-set conditions and other metrics defined in other sheets. Background on existing sheet: The existing sheet is used by managers at a quick service restaurant (like fast food) to allow easier and more accurate projection of future shortfall in cash. The sheet gathers data from a “daily sales sheet” that staff enter daily sales split by branch and split by cash and credit card sales. The sheet also includes other columns on sales made to other companies on credit basis. The data on the “daily sales sheet” flows through a “cashflow forecast sheet” which forecasts future sales trend using “trend line” function. The “cashflow forecast sheet” also takes into account all scheduled payments and gives management net cash figures available for spend on a daily basis. The purpose behind the existing sheet is to provide better visibility Incase there is future shortfall in cash and allows management to better control how to manage cash. Phase 1 or new requirement: The first phase of this project is we need to create a sheet that automatically determines which date a new Cheque payment can be scheduled for. The new sheet must take into account cashflow forecasts from existing sheets, and use parameters (entered manually) of maximum cheque payments allowed per month. Example: monthly cheque payment limit = 100,000 Employee enters new payment to be issued by cheque on a sheet, this information is then used based on the limit determined above and the forecasted cash available to suggest and recommend a date for payment and so forth. Phase 2: revamp existing “cashflow forecast sheet” to estimate better and more accurate forecasted sales figures based predominantly on pre-existing data Phase 3: combine all information into single dashboard to allow better decision making and better cash management