Visit https://www.gnu.org/software/pspp/ to learn about options for installing PSPP for your own computer.
Download and install the version appropriate for your operating system at https://www.gnu.org/software/pspp/get.html .
While SPSS permits simultaneously running descriptives for multiple variable types (nominal, ordinal, or scale), only certain options are appropriate for each. To avoid confusion if you are still be learning about scales/levels of measurement, there are separate videos covering each type. You should watch them in order as each level of measurement builds on the previous: