I'm no plumber. But I have done that a few times.
Pretty straight forward really. The 1/2" copper pipes that run through your walls connect to a threaded pipe (3/4" ?) that is a standard thread.
I don't know your situation entirely. But what I'd do is shut the water off, at the meter, somewhere out in your yard, or wherever it is. Open the taps, to drain all the water out. Then take to them with a shifting spanner. Just look for flat surfaces that will take that shifter and you'll dismantle them eventually.
I'd just take these old fittings with you when you go shopping for the new taps etc. And just produce them to compare with the setups your considering to buy. Or just ask the sales bloke etc. Pretty straight forward though. Just, have to be prepared to have no water at home while your shopping.
Get some plumbing tape while your out (white stuff) and just wrap those old threads heavily before winding on the new taps. If you don't do this well enough, you might get a leak into your walls. Not good. Heaps of tape, such that it takes a fair bit of grunt to wind the taps on is good. May take some trial and error.
Then get your misses or whoever to turn on the tap on your command, out in the yard......'TURN IT ON NOW ! '........' WHAT ?! ' ........' I SAID, TURN IT ON ! ' .......' WHAT YOU TALKING ABOUT! ITS ALREADY OFF!' :confused: ....
goodluck(if you stuff it up, don't blame me, ok)