Simple Expense Summary — The Simple Expense Summary presents sales information for a group in AdventureWorks over a single fiscal year. This sample consists of three tutorials that demonstrate the basics of designing a report with ExcelTemplate. By the end of this sample you'll be able to create reports with data, formatting, formulas and charts with as few as five lines of code.
Extended Sales Summary — The Extended Sales Summary presents some grouped sales information for a single fiscal quarter. This sample consists of two tutorials that present an introduction to the ExcelApplication object and how to use the ExcelApplication object in combination with ExcelTemplate. By the end of this tutorial, you will be able to create a dynamic template with copied sheets and a coversheet.
Financial Report — The Financial Report presents assets and losses divided by quarter. This tutorial consists of three parts that cover the use of data marker modifiers and template formats. The tutorial also covers using ExcelApplication to copy between two workbooks. By the end of this tutorial you will be able to format data markers and post-process on multiple workbooks.
The resources here will help you get the most out of ExcelWriter.