Extensive Excel workbook into Salesforce

We use an extensive excel workbook that I filled out each time we start building an opportunity. I would like to find a way to have it built directly into Salesforce. It get complicated because there may be one workbook that only has a few lines in one section, but another workbook may have 10 lines for that one section. I would like to discuss with someone to steps they would take to build this. I can also forward a blank copy of the workbook.