Pretty easy mate. However i would recommend changing pads at the same time. Reason being is your existing pads will be "moulded" to the shape of your old rotors and may not have optimal contact with the new rotors. Can cause hot spots on your pads and bake them. It's not a pretty sight pulling up at the lights with smoke billowing out of your wheels.
1. Remove wheel
2. Unbolt caliper from hub ( 2x17mm bolts on the back) and pull off rotor.
2.5 May have to remove the dust covers if still attached, usually 3x 10mm bolts. Leave them off and bin them.
3. Give the old rotor a tap to dislodge it from the hub.
4. Slap on new rotor
5. You may have to push the brake calipers apart a little to clear the new rotors as they will be a little thicker than your old ones , just push against the pads a bit to give extra clearance. Don't push too hard as you may cause the brake master cylinder to leak out brake juice.
6. Bolt caliper bake in place. Check your pedal travel is all good before you put the wheel back on.
7. Put wheel back on.
Done!