Maybe write her an email just explaining how you feel and let her know while she's gone you'll do your very best to effectively utilize the systems. It's unfortunate that's she's leaving when you need her the most.

this is why Google was made ☺

What kind of program is it? Don't be afraid to use google to find answers or tips on how to use the program. Any issue you run into, odds are someone else has as well.

Trial by fire! Hope you took notes. Remember most programs have a help file or manual.

Youtube tutorials will be your best friend here.

It's called the Internet, it's full of lovely tutorials and information, use this to your advantage and show your boss that you can adapt to the situation. It will get you far my friend. Good luck.

Why does everyone assume the OP has not heard of the internet or Google? Also, some problems still aren't on the internet- there are plenty of times I've had problems with freakin' adobe that no one can answer, and that's about as common as you can get. Sorry OP, that's rough. No idea why a boss would hire someone new and then take off, unless you were hired specifically to cover their vacation.

Better get that person phone number to bug her. That's what you get haha

Time to show them what you're made of. Rise to the occassion

You should document that. That way if something happens while she's gone and then tries to put all the blame on you, you can take some proof to HR that it isn't entirely your fault because you were not properly trained.