If you are new to the NSCP Client and Nagios here are some basic steps which must be done to get it working. So for nearly any monitoring script which you can find here on this project the following steps must be done:
1.) On the server which you wish to monitor install the latest NSCP client (download here; which is at the moment a 0.5.* version).
2.) Once downloaded and installed you need to perform a configuration. This configuration is (if not changed) handled by the nsclient.ini inside the C:\Program Files\NSClient++. You can find a basic configuration here, which might work for you as well.
3.) The next step is to create a folder called "NagiosMonitoring" on the server you wish to monitor. Put the needed *.ps1 monitoring script inside that folder. Sometimes the *.ps1 files must be configured due to the reason that they need a special taskuser. You will find more infos what must be done inside the files or in the documentation for them.
4.) Once the basic configuration is done you need to adjust the nsclient.ini and point it to the script (in the folder created in step 3). These scripts must be mentioned in the section [/settings/external scripts/scripts]. If you check the default configuration here, you have a starting point.
5.) If everything is done, you can restart the NSCP Service to ensure it reloads the config and you are done with the configuration on the server.
6.) The next step is to configure Nagios, so that Nagios query the Server and the installed NSCP client, trigger the script and read out the information.