How do you create a checkbox using Spreadsheet Gear in C#?

I need to add a checkbox in Excel using Spreadsheet gear. The documentation for Spreadsheet Gear is terrible and doesn't include any methods or info on how to initialize these properly. How do you:

1. Create the checkbox object using correct syntax
2. Add Alt text to object
3. Control check true or false feature - I see this may be checkboxtrue or false methods but want to be sure.