front one just clips off, just get a screwdriver and prize it off, get a cloth inbetween to not damage it and just be gentle and it will come off.
The back one is a bit harder, open your boot, take the plastic off the backing, you will see 3 8/10mm bolts i think they are in a triangle, take them 3 off and prize the big black lump bit at the back off, you will need to use a slight bit of force if its never been off.
Then you will need to take the plastic welding off the back of the rear badge to remove it from the car part. just use some apoxy resin or some other substance like that to put the back badge back on.
Hope that helps