Unzip the files into the FS2000\Aircraft folder
Copy the gauges into the FS2000\Gauges folder

For the english version only
Rename the file Wilga-M_CHECK.TXT to Wilga-M_CHECK.GER
Rename the file Wilga-M_CHECK.ENG to Wilga-M_CHECK.TXT

The references file is written in both languages

that's it