How do residents parking permits actually work?

It looks like they'll be in Dennistoun soon, obviously pumped to have the privilege of parking outside my own home but I've never lived anywhere with them before and I don't really get how they work. What radius from my address can I park in before I have to pay? If I live at one end of Dennistoun but I park outside the post office or whatever on my way somewhere, do I need to pay or does it cover the whole area? If someone visits me for the day are they paying 1.70/15 mins or whatever extortionate amount it is to be here, or is there any other option?