This Microsoft Excel template illustrates how to create a loan amortization schedule, as well as dealing with additional payments and variable interest rates. Step 1: Set up your amortization table.Open a new Excel sheet and create input cells for the known components of your loan. The indepth Watch Me Build is a 25 minute behemoth, showing you how to build a more complex, dynamic amortization table in Excel. Adding extra principal payments in order to pay off the loan earlier than the loan contract calls for. In this tutorial we will add this feature.