On the down side, engaging a tax expert cost me a lot of money, plus I got audited and had to pay fines to the IRS a few years back. I looked back at previous years, and he had made a lot of mistakes! I had no recommendations for someone else (good and affordable).
The first time I filed the business forms (Schedule C) I did make a small mistake. Caused a letter from the IRS and phone call to the IRS. I got a really sweet gentleman with a TX accent who helped me resolve it. I simply had to resend the corrected forms and no financial consequence. I dread talking to them so I was pleasantly surprised.
Here in the US, it is quite expensive to pay a tax accountant for a small business tax filing. For most people selling soap and other BB products, it is not affordable.
If you can figure out how to run a business, you can probably figure out how to do your taxes. As far as the business activity code, pick the one that best describes what you do, there is only room for one and there is not going to be a perfect description of everything you do. Just pick the one that describes it the best.