The easiest way to get comfortable is to buy a gf flour that is a cup for a cup replacement. Make sure that it includes a gum. Then you can use any recipe that you are used to and replace the flour. In general a recipe with less flour will taste better. Chocolate cupcakes are great.
Yes, you can buy xanthan gum (we use Bob's Red Mill) and add some to cakes/muffins and challa. It helps to make them more 'springy.'