Using a sharp knife, carefully cut a seam in the abdomen, taking special care not to pierce any of the organs or body cavity, which can ruin the skin. The most commonly used materials are borax, non-iodized salt or alcohol. When using salt, rub it into the flesh part of the skin and let it sit for 24 hours. Repeat the process but with new salt.
Afterwards, let it dry in a cool, dry place, being careful not to let it harden too much. The first step to being self-taught in the taxidermy trade is not to be overwhelmed by the variety of skills needed. For example, one might be intimidated to wonder how to catch fish, birds, life-size mammals, and game heads. Forget about the varied selection and focus on one discipline.
I have friends who mainly hunt birds, so they naturally learned and mastered bird taxidermy. Most big game hunters are attracted to shoulder mounts, so that would be the best place to start for most It just takes good information, a moderate amount of practice and a willingness to pay close attention to detail. Anyone can do a bad taxidermy, but to avoid being a hackidermist, you have to worry about detail and accuracy. Once you buy a DVD, you can watch it and see if taxidermy is something you think you're capable of doing.
If so, most DVDs will give you a list of the tools you need and where to buy them. I told you it was easy to get started. The tools needed for a deer shoulder mount aren't that expensive or complicated. You'll need a variety of small hand tools and a couple of larger appliances that you can buy or build yourself from available plans.
Trust me, it's all on the Internet. You just need the desire to learn and the means to stay engaged. The taxidermy website mentioned above has tons of free tutorials, but the best resource it contains is a network of hundreds of active taxidermists. If you can master the art of tactfully asking for help, the sky is the limit with your learning.
Most taxidermists hate lazy novices who ask silly questions, so learn everything you can before you start and then try to ask somewhat qualified questions. Taxidermy schools are a thing of the past and an ambitious person can master all the skills needed to complete durable, quality mounts.