It takes time and patience to learn to use and become good at using a chainsaw ,but it is well worth it. Some of the more important things to consider are the types of wood your going to use.I would like to start off with pine.It is a soft and very straight grain type of wood with some knots in it.The best will be a log that is dried out just a little bit and straight.Oak will be another great piece of wood,but this type of wood is a lot harder and heavier to handle.Always remember looking to see that the log is straight and has very few limbs on it.I would suggest to place your first block of wood in a safe place to work such as there will not be any debris to stumble over while your working on your carving.
I have here below a 3 minute video with a very well seasoned and talented carver.