I understand how they works but there are parts I don't understand. Are they like flasks and last a certain peroid of time? If not, do you attached them to pieces of gear? so you can have tanking glyphs on tank gear and dps glyphs on dps gear? Thanks for clearing these up for me.
You have an extra tab in your spell book. You just put them in, similar to gems into sockets. They are permanent and can be replaced by new runes (again, similar to gems)
Would you like to know more?
http://wotlkwiki.info/index.php/Inscription is alot of info.