The .js files and excel files below demonstrates how you can use an Excel spreadsheet as input for making load combinations.
The files in this example can be used together with the B2 example. You can easily adapt them to suit any model.

Start by creating a new workspace.
Read in the B2 example that can be found in Help | Help Topics | Example Index
Copy the following files into the workspace folder (choose the .xls files if you are using Microsoft Office 2003 or older):

ListAllLoadCases.xlsx / ListAllLoadCases.xls
LoadCombOverview.xlsx / LoadCombOverview.xls
ListingLoadCasesInExcel.js
excel_example_make_LoadCombs.js

Study the file LoadCombOverview.xlsx in Excel. This is a file that lists loadcombinations to be made in the B2 model.
Read in the .js file excel_example_make_LoadCombs.js.
Observe that the loadcombinations are created in GeniE.

If you are using this method on a model with many loadcases, you can start by reading in the .js file ListingLoadCasesInExcel.js. This file will make a list of all loadcases in the Excel file ListAllLoadCases.xlsx. You can then copy and paste these loadcase names from ListAllLoadCases.xlsx to LoadCombOverview.xlsx.