Best advice just starting out in something you know little about———-K.I.S.S.!!!!!!!!
When it comes to food in general, people feel most comfortable with brands they know and trust like Sabretts, Hebrew National, Vienna Beef, etc. To try to start up with a no-name proprietary brand dog is not advisable. Find out what sells best in your area and go with that. People will buy what they’re used to eating.
IF and thats a BIG IF, you’re successful, you can experiment with other products later.
Home-made Syrup/Soda???-Feggetaboutit! That’s for  the future after you’re wildly successful. In the meantime, stick to the basics, Coke, Pepsi, etc.
Buy a used cart.
Don’t buy a software package.
Employee scheduling??? YOU’RE it!
Catering Planning?? Don’t need it.
Menu management?? Put it on a whiteboard!
You’re a one man operation, not McDonalds!!
Stick to the basics.
KISS!