They are intended to be used like a barrette, but they do not stay in well at all. There are some fixes for this, but it depends on how permanent you want them to be on the doll.
they are supposed clip like barrettes but it looks horrible. It looks like she is pretending the be a cat by putting fake ears in her hair. Some people clip the tabs off and glue them to her head. Some clip the tabs and poke the stubs through her head. Some put a small slice for each ear in her head and feed the tabs through. And there is someone who makes headbands for the ears. good luck
I agree with above that putting the ears on like barettes looks hideous.
For what I did and it's really easy:
Clip off the tab of the ear which will leave only the peg on the base. Clip as close as you can to the base. Wire cutters are great for this.
with the wig on the doll, manually position the ears about where you want them. Put down one ear, then place your finger right where the peg meets teh wig, put down other ear and carefully mark the plastic of the wig with a marker dot. double check it's placed right then take the wig off and make a hole in the plastic of the wig with an icepick. This is actually really easy so be careful not to pierce yourself or your finger.
Push ear peg through teh new hole nd put back on your werecat. hold the other ear to the head again untl you find it in a good looking position and then repeat the same process you used with the first ear..
If the ears aren't exactly wehre you want them, you can just put another hole in the wig to better position them. One side of my werecat's wig has three holes in it. I used a Liv wig but I think it will work jsut as well with a monster high wig.