Hard? Not really. In a busy lab you will feel rushed at times. My lab in Atlanta averaged about 100 rolls per day and we had 3 staff on hand all the time. That was before digital. My lab now, in rural NC only averages about 20 in slow season (now) and about 40 during holidays, down from about 80-100 in 2000. However, we do between 20,000 and 35,000 digital prints a month on 4 different dye-sub printers.
I have never worked for Walgreens, but I imagine it is similar. In my lab, a pre-requisite for hire is an interest in photography. You don't have to know everything or be a professional, or even an advanced amateur. But I have found that people who like to snap pictures understand better what is needed to help Joe Consumer in getting his/her photos done and being pleased with the results. They may send you to an organized class, or the lab manager may train you. You will learn what services your lab provides and how to assist customers in placing their order. Then how to extract and load film for processing. How to operate the printer/processor for film and digital. How to load paper. Maybe how to mix chemistry. If you will be opening, how to run and plot control strips. Putting the machines to bed in the evening. More advanced training would include setting parameters for the machines, balancing paper channels, emulsion changes, routine and special maintenance, dumping and re-mix of chemistry, rack maintenance and cleaning, inventory control, cleaning filters etc etc etc. That's the easy stuff to learn.
The much more difficult part of anyone's training is teaching a new employee how to see color and density. Color negative film often needs correction when printing to get the best quality prints for the customer. Some people cannot see that a print is magenta or red, or blue or green or cyan. (Most people can see yellow) In order to correct a color cast, you first must be able to tell what color it is. Hard for some people to grasp that concept. Also, what makes a good print is subjective. Over the years, (if you stay with it, as I have) you will come to know your regulars and how they like their prints to look. Customers even have their favorite tech and ask for them by name.
I have always said to really enjoy working as a lab tech, you have to be a bit voyeuristic. Otherwise you will get tired of looking at other people's often mediocre and poorly done snapshots. If it is for you, you will find it rewarding and your interest will renew daily. If it's not, well that's OK, too. It ain't for everybody. You will also hear the pros poo-poo one hour labs, and many deserve their bad reputation. And while a minilab cannot do many things a professional lab can, a good one is a great thing to have available.
One more thing, please PLEASE wear gloves or finger cots when you handle customer's film. The oils from your hands can cause permanent damage on the surface of negatives. If the lab manager doesn't require gloves, then he/she is not a first rate manager, because that is step number one.
I hope you enjoy your new job!