I was a console and laptop guy for my whole life, built my first PC I think age 32-33. It was initially daunting but /r/BuildaPC and analyzing many builds on PCPartpicker.com really helped. I also had a couple of people at work who helped me physically assemble it, which was huge.

Honestly, it's much more straightforward than it seems when you think about how complex PC internals seem without much prior knowledge. I would say find some builds you like on PCPartPicker.com and try to emulate them. When it comes to assembling specific parts together, find YouTube videos that closely emulate your setup. For example, the last PC I built used a Lian Li mini case which is very small and can only house very specific sizes of some parts (mainly MoBo and power supply). But it's a very popular case, so there were a ton of very detailed youtube videos on doing a Lian Li mini build. That stuff really helps.

Another thing, highly recommend getting some type of screwdriver / tool kit like this: https://www.ifixit.com/products/mako-driver-kit-64-precision.... I am sure some frugal stickler will come along and tell me why I am dumb for overpaying for this kit, but I really enjoy the convenience factor and did not exactly have a robust set of hand tools laying around - which I expect is the case for many building their first PC.