If the business activities are closely related you could combine them into a single Schedule C, but in your case it sounds like it should be two separate Schedule C's. The loss from one will offset profit from the other, and your self-employment and income taxes will be based on the net of the two businesses.
Any business can generate losses, make sure your expenses are reasonable and documented, there are plenty of resources out there for helping you decide which expenses are proper for each business.
There is some truth to the warning that not showing profit in 3/5 of years can raise flags at the IRS, and they may deem your business a hobby, which disallows losses. That is not a hard rule, legitimate businesses can lose money for years on end without issue, if you're trying to make money at it, you'll likely be fine.