These two files contain the same spreadsheet models in two different formats, Open Document Spreadsheet (.ods) and comma-separated values (.csv). Most modern spreadsheet programs should be able to read the former, which is somewhat more pleasantly formatted. The latter is a text format often used for program input or output of tables, and should be readable by every spreadsheet program.
There are three tables in the model. The first is an approximation of the US national income statistics for 2015 from the Economic Report of the President 2018. The numbers are rounded to very imprecise values to make it easy to read. The simulations are too simple to accurately estimate the outcomes, so no important information is lost.
The second is a simulation comparing financing the government with balanced budget under the current tax rules and under a system with a universal basic income, universal health care, and a flat tax. Users can adjust the levels of basic income per person (base case $10,000/year), health care expenditure (base case 1/9 of GDP), and infrastructure investment (base case 0). It provides a comparison of aftertax income at various income levels.
The third is a simulation comparing financing the government with balanced budget under the current tax rules and under a system with a universal basic income, universal health care, and a value-added tax (VAT). Users can adjust the levels of basic income per person (base case $10,000/year), health care expenditure (base case 1/9 of GDP), and infrastructure investment (base case 0). It provides a comparison of aftertax income at various income levels. Users should beware that in a simple simulation like this one, it's not reliable to compare incomes across income tax and VAT systems, because VAT doesn't tax income at all.