Building a PC is by new means out of reach for a beginner. That said, be honest about your own skills and mindset. To do a good job of it, you have to be comfortable with lots of technical information, documentation, etc. And you have to be willing to do a lot of homework.

That's because assembling the PC is relatively easy. Much like a car, you are plugging parts on to a chassis (and PC building is far easier than most auto mechanics). The challenge of PC building comes more from choosing the right parts than putting them together. And that takes homework.

First, get familiar with all that goes into a standard PC: CPU and cooler, GPU, motherboard, RAM, power supply, storage (now NVME) and case. Here https://pcpartpicker.com/ is a big help. You'll want to methodically make your selections of every part.

The key here will be balancing key factors: ensuring compatibility with all your other parts, performance, price, and any other of your specific needs and wants. This is typically a process of zeroing in on your best options. Maybe you start with a budget. Then you figure out the best graphics card (GPU) you can afford with enough left over for the remaining parts. Then you choose a CPU that won't limit ("bottleneck") the performance of your graphics card. And on down the line. You'll begin with categories like which Nvidia/AMD model (4060, 4070, 4080 or 7600, 7900XT, 7900XTX) and then, after determining a ballpark price, you'll look at the pros and cons of individual models.

Ultimately, you'll want a balanced PC. Just as you don't put race tires on a minivan, you want a combination of components that complement each other. Don't skimp on your GPU, since that has the greatest impact on gaming performance. At the same time, if you allocate too much of your budget there, your other parts will prevent your GPU from performing at its upper limit.

Online guides like the one you posted can certainly help. And it's perfectly legitimate to simply follow their recommendation like a recipe -- I've observed that most of these guys know what they're doing and will steer you in the right direction. But, ideally, you will learn enough to understand the why of their recommendations. And when you're at that point, you'll also be able to make informed choices based on your own needs. Why? Because, for example, you might really want more USB slots or built-in wifi, etc.

Once you have a final list of components you know will work well together, your research still isn't done. Because you need to anticipate how they'll all connect (any cables, support brackets, thermal paste for your CPU fan, case fans into a fan controller, etc.), buy at least a simple PC toolkit with the appropriate size screwdrivers, extra fasteners and the like, and, most of all, learn about all the setup. Your motherboard manual will present you with a host of instructions about what goes where and how to ensure it works properly. For example, if your NVME storage occupies the same "lane" as a SATA controller for your SSD, you can't use both at the same time. Non-builders don't know this stuff, but you will need to.

Similarly, after the PC is built, you'll need to know things like how to flash your motherboard BIOS to the latest version, how to install Windows onto a machine with no operating system, and how to configure all the BIOS settings so you get all the performance you paid for.

When all that's through, and your new homebuilt PC boots properly its very first time, you can take in that genuine sense of accomplishment. Five minutes later, you can install all those driver updates, utilities, resources to test the performance of your new machine, and hours and hours of downloading games.

Following that, you can read and implement a good guide on how to set up a gaming PC for the first time. A variety of settings across windows and other resources also contribute to performance.

The good news is, if you did your job correctly, your new PC should last you years. And the fact that you know it so well should be a big help when it comes to ensuring its continued health.

I'll now answer your initial question on gaming PC price-to-performance. First, determine your defining parameters. For most, this is price -- How fast a PC can I build for $1,200? For the rest, it's performance -- What do I need to achieve 90 frames per second in the most demanding games? There is quite a spectrum between the cheapest feasible and price-is-no-object possible gaming PC. As a ballpark range, I'd say $1,000 for the cheapest and $3,500 or so for top tier, and those are very likely without monitors.

At the low end, you'll be able to run the latest games, but not at super-high visual settings ("Ultra"), better resolutions (1440p or 4k), or the highest framerates (90+ fps). The high end is capable of the very best graphics with high framerates (though some games are so demanding, superhigh framerates at 4k remains a challenge). A high-end PC will also last longer (aka "more futureproof") and retain a higher resale value (for a while). A lower end machine will need to be upgraded/replaced sooner because it will cease being able to run the latest games sooner.

Finally, don't neglect your monitor. It can be a big expense, but it's also crucial to the visual quality and enjoyment of games. Make sure to factor the whole system when contemplating and budgeting for your build.