Need to know what to mold the leaves to & if I can use fake leaves
You can use fake or silk leaves. To shape them I would suggest turning a bowl upside down and dipping the first layer in the Modge Podge glue, then gently pressing them to the bowl to shape the entire structure, one layer at a time. Once dry you should be able to remove your leaf bowl fairly easily. I suggest a glass bowl. I have seen these done using an inflated balloon as a mold too and then popping and peeling the balloon once it dries. Just shape the 'bowl as far up the balloon as you need to get the size of bowl you desire.