I am new to this fondant / birthday cakes but my daughter wanted me to make a cake for my granddaughters 5th birthday using the Wilton number 5 covering it with white fondant and purple circles. My first problem is when I ordered the cake pan (ebay) it came in as the shape of 5 but it so small -

My question is do I put this on a square sheet cake (support ?) ...and than cover it with fondant. I looked through the recipes and get myself confused on which cake recipe to use to hold up to the fondant and than what fondant recipe to use for such a rookie as I am - but being a proud grandma I want to make this for the party but don't want to make a mess Lol Any help would be so much appreciated -