Asp.net/c# page to fill-in Excel template with data from json

I would like you to build a web page in ASP.NET/C# to create Excel files. The purpose of the page is to receive json-data from browser, open an Excel-template, insert json-data to Excel sheet with some quite simple rules and send the filled in Excel file back to the browser. The source code should be simple to modify afterwards, e.g to add more data or change/add formattings. The data is a hierarchical set of rows and columns. You don't need to calculate anything, just iterate rows and columns and set values to cells. You may use your prefered server compatible components for Excel operations (ExcelLibrary, OpenXml, Recordset,..?) and json parsing ([login to view URL]) but please inform what you will be using and what licencing the components use so that we can make sure that they fit in the architecture. I will send you multiple actual json files and an excel template file so you can test with real data. Attached is a sample result after combining data to an empty template.