How does one “engage”(?) with a block chain?

OK. 1. Let's pretend I'm a 5 yo, but I've been around for 45 years. I have only ever used so-call "web2" platforms, and have never in my life coded (accept in a class in hs in the early 90s, would have no idea what to do with a server if I had one, and have never used a platform that didn't just "run" once you downloaded it. In other words, let's assume I'm everyone who's never heard of HN. How would you explain to me how to access (is that even the right word?) a blockchain?

2. This seems like the right time to ask this, as I have a feeling it deals with the same thing. If I wanted to play around with something like this Zooko thing (https://news.ycombinator.com/item?id=29912396) which I don't necessarily, I just think it's a good example, being the person I mentioned above, how would I do that???

3. Are there books I can read so as not to bother the HN community?