I need to make a large cake, 14" x 14" and need a recipe, I can only find recipe for up to 10" just need a plain cake nothing fancy also any tips on cooking a cake of this size.

It isn't likely you will find a recipe for an exact 14x14. You will most likely need to do two recipes and make the remainder in to cupcakes.

For a pan that large, be sure to use bake even strips or inverted flower nails for heating core. That will help the cake bake in the middle.