An autoland is, as it suggests, when the aircraft automatically lands itself. By that I mean it will fly down the glideslope and along the localiser and once it senses it is over the threshold via the radalt, it will perform the flare and roll-out itself. Some aircraft are even more sophisticated (the A320 is one) and will reduce thrust and steer down the centre-line once on the runway - all automatically with no input from either pilot.
The pilots are still responsible for configuration changes - gear and flaps, deploying the thrust reversers on landing, and braking if the autobrakes don't work. We can also control the speed at which we fly because the aircraft doesn't know, for example, that it is getting too close to the aeroplane in front and therefore needs to slow down. However if we don't need to fly a requested speed from ATC we can let the aeroplane decide when it wants to slow down (flying over the 'D in a circle' to activate the approach) as long as we are in "managed speed" (i.e. the speed knob has been pushed, not pulled so there is no speed showing in the MCP window).
It will then slow down until it gets to "Green Dot", "S" speed or "F" speed which are minimum speeds it can fly at without having to extend slats or flaps (these speeds are on the left of the PFD on the speedtape). It won't go below these speeds because otherwise the aircraft might stall, so it waits until we extend the flaps before reducing speed further. If there is a speed constraint in the FMGC - either part of the procedure or because we put it there - it will adhere to that as well.
I have to admit I did give you a bit of duff information earlier in that you can do a CAT III single approach on 1 autopilot, which is why you are getting that on your flightsim. But if the aircraft and airport are adequate we will always fly the highest category approach available for an autoland (CAT III dual). This means that when it is really foggy, we don't have to be able to see anything and the aircraft can continue to land.
Also, if you are cleared for the approach, you don't have to select LOC and APPR; APPR arms the localiser as well as the glideslope. You only need to select LOC if you just want the aircraft to follow the localiser and not to capture the glide - maybe you haven't been cleared to descend by ATC or you are just doing a localiser only approach!