What skills do you need?
To build something like this using Power Platform, you will need certain skills, of course. A background in IT makes designing functions easier, but it's not a strict requirement. The most important thing is to have a clear idea of your end result or goal, and then figure out how to get there. If you're analytically inclined, this can prove helpful in identifying the right steps to take. Persistence and ingenuity are also useful traits in problem solving. Seek and you shall find!
Generally, developing an app or automating a process will go a lot faster if you're already familiar with the business challenges that need solving. That's why Microsoft encourages citizen development, where employees create business applications and features for their own use. It gives them an opportunity to move beyond the usual daily tasks and dream up innovative ways to improve their own business processes.
Resources to get you started
Once you've found a business challenge you'd like to tackle, it's always advisable to start by gathering information on that topic. For instance, you can look for others within your organization who have experience with the challenge and work with them to define the process. In many cases, this stimulus is all you need. You can probably handle 80% on your own; only the final 20% will require a bit more research.
YouTube is a good place to gain inspiration. Often, seeing some actual code will be enough to help you along. Useful channels include those hosted by Shane Young, April Dunnam, Reza Dorrani and Microsoft Mechanics. Blogs are also great sources of information. It can be very stimulating to learn about what other companies have achieved with Power Platform. Don't forget there's an entire Power Platform community out there too. Your most burning questions may have answers already, and you can even get help with specifics.
Microsoft also provides more formally structured learning opportunities. On successful completion of one of these courses, you even receive a certificate. PL-900 Power Platform Fundamentals makes for a great introduction. For example, it teaches you which elements of the platform are best suited to solving certain problems. Power Platform App Maker Associate (PL-100) goes a little further, describing how to build an application.
Answering the question: rocket science or child's play?
As always, the answer lies somewhere in the middle. Sometimes building an application is best left to the experts. Especially if the app must be incorporated into complex architectures or draw on databases hidden behind firewalls. In such cases, you are really moving beyond Power Platform's safe walls and venturing into the intricacies of the actual system. The platform is simply a toolbox full of handy components. Once you've familiarized yourself with these components and started using them in imaginative ways, it will become child's play soon enough.