If you find text like...
...written in the Forums, you can copy and paste it into your mIRC remotes (press ALT+R to access it). This will appear in one long line however, and you will need to carefully split the lines up so that they match the code posted in the Forums. Do be aware that nobody can really be held responsible for the code found on these Forums except for the person who posted it, however, any code that is posted will most probably be deleted when it's found, so everything on the Forums is safe to use, but might not necessarily work.
Any GOOD script that you download will have adequate documentation that informs you of what to type, and where to put files etc etc. One of the best websites to get scripts from is
www.mircscripts.org as they check their submissions for viruses, and review all of them too, so you get a good idea of what it's like.
Although /load -rs is the most popular command used to load a script, it does not always work because it loads code into the remotes - not all commands are supposed to. You can find help with the /load command by typing
/help /load whilst in mIRC. The term "add-on" is there because it is adding something on to mIRC. Add-ons are separate files which do not attach themselves to other scripts, but create a new remote file. If you type
//run $mircdir (again, in mIRC) you will find all the script files there.
http://helpdesk.zaz.net is DALnet's #HelpDesk website (which is the network's recommended scripting help channel) and is an excellent resource for people who want to know more about scripting and how to do it. There is also a lot of info contained in the mIRC help files, accessed with the simple
/help command.
As for the script you want, you can search ms.org's
addon section and see what they have. Try "Away" as a keyword. You can search other scripting websites too, search
Google for 'mirc scripts' and you'll come up with a lot of websites. It's very very important however, that you scan everything you download with an up-to-date virus scanner. You might like to use
AVG if you have not already got one.
As for people thinking you're stupid, don't worry too much about it heh - it's your mIRC client, it's your IRC chat experience, you can do what you like if it's not abusive to other people, and provided OPS of a channel are not asking you to stop it

Happy chatting, and hope this helps a little!

Regards,