At the top right-hand side of the Modelling page you will find the Date Range and Rate of Demand (RoD) selectors. These are set by default on the last 12 months and Per Month respectively.

Selecting different date ranges or RoD will auto-recalculate the RoD for the selected products.

By default the Modelling tab will load with no products selected. Filter the Modelling page using the Chart Filter panel or the drop down menus to select products to begin modelling.