I will post here and on their wall or if they don't have their wall active I will pm but I always post in both places just so everyone can see who the winner is. If you mean how will I pick the winner first as I posted it will go to the most poster, if no one posts more then once then I will use random.org to pick and will also post a screen shot of the drawing.
I am getting excited about this. Out of all the giveaways I have done over the years for different sites this is one of the ones that makes me very happy because I get to help complete someone's museum!