Step 1: Materials
Clay tools-nothing crazy outside the standard set at a craft store.
Small paint brushes-also nothing special
A sketch- the more angles you can do here the better off you will be. Draw your creature from straight on, up,down,back,front..ect. I kinda skipped this part and paid for it later. The less you draw out now, the more you will go of back and forth with clay (which takes much more time). So take your time and plan it out. Now to get dirty.
Also check out my artist warmup to help you get started.