Download and install the Skript plugin (put the jar in your plugins folder). Generate the Skript data folder, and put your <script>.sk file in the scripts/ directory.
Okay I installed it, but it did not create a new folder, for the skripts, seconds the things I get are only pastebins, so I'm not sure if I have to write them anywhere?
Restart the server to get a Skript data folder. For the pastebin skripts, copy it all into a new notepad file. Save it as anything you wish, but the file extension must be .sk e.g. counter.sk