To install PRIS on Microsoft Windows you have to install a current Oracle 8 JRE.
Make sure your java binary is in your search path.
Download and extract the latest stable release as ZIP archive from GitHub.
Extract the ZIP archive in a directory.
You can start PRIS in background using the opennms-pris.bat file.
If you want to start PRIS as a Windows Service you can have a look at the NSSM Tool which allows you to add custom Java applications as service.