Under most any circumstances, RGSS scripts are inserted (copy/pasted) into your project's
Script Editor (F11 bring it up). I'm saying most of the time, due to some scripts requiring you to 'edit' a few scripts here and there... and with detailed instructions on what to edit. But for the most part, you paste the whole script into your project in between the
Scene_Debug script and the
Main script.
Some scripts include features that you can turn on or off... or other editable values (game speed... custom names.. whatever). These things are usually found in the script's configuration or setup section.
@my_mapname = true
@my_mapcolor = color.new(255,255,255,255)
This is just a sample of a couple switches. Let's just assume that this little snippet of a script turns on/off a window that shows the map's name and set's the text's color, shall we?
Please check the post for other options.
Also, some scripts require other materials such as audio files (sound effects for menu functions) or graphics (icons for custom menus or special 'battlers' for custom battle systems). If these files are not supplied in the topic, then you may want to check the topic on how to add or use your own resources in their place. Thank god for the Resource Analysis section, eh?
'Course the best way to get a script is to download a working demo. Right?
Just read up on all the features from the topic where you downloaded it and you'll do fine. Start experimenting and maybe you'll become a scripter too.
Edit: She beat me to it. That's 10 minutes of typing for you....