If you want to learn how to build a PC, just having a go is probably the best way -- though if you do mess up somehow, it can be expensive. One of the cheaper ways to learn how it all goes together then, and give yourself access to much more fanciful hardware, is to use PC Building Simulator. A new update for the 'game' now lets you overclock the system too, playing around with settings and BIOS options to achieve optimal clock speeds for your various components.
The update is pretty comprehensive too. Not only can you adjust CPU frequency multipliers, but you can also tweak your RAM speed and voltage, Vcore, GPU clock speed, graphics memory clocks, and more. You do so within the BIOS and within a bespoke GPU tweaking application all within the game. As PCGamesN highlights, there's even a stress testing application you can run on your virtual system to see how well it runs after your overclocks have been applied.
If that all seems rather easy compared to the real deal, there are other factors to consider. Every component in the game has their own unique thresholds for overclocking potential, just like in the real world. Some chips and cards can just be pushed further because of fewer defects in the fabrication process and that's exactly the same in PC Building Simulator. That means that you're never guaranteed a strong overclock and could make for some decent competitive elements in the game that weren't present their before.