Nobody has actually asked these yet, but I anticipate them coming.

How do I add these to my neocities?
If it's a javascript sidebar thing, see the instructions in the example. It's mostly copy-and-pasting.
For a template, download the zip file, and neocities will let you drag-and-drop them right into your site dashboard. IMPORTANT: unless you kind of know what you're doing, do NOT put the files in different folders, because that changes the URLs and makes it hard for files to cross-reference each other. Don't rename them, either, unless you're going to find all the places that file was referenced and rename it there too.
Wait a minute, why does the template I downloaded have ugly colors and comic sans?
Because I want to get you to customize your site. That's the whole point of Neocities: make something truly yours, get your hands dirty and do some web design. I've made changing the color pallete as easy as changing the variables at the top of the CSS file. Find some fonts and colors you like!
Really though, if you wanted something ready-made, go join social media. I don't want to deprive anyone of the experience of making a unique page to call their own. I just want to make facing a blank page less intimidating for those who are new to this.
How should I credit you?
You don't have to, but it would be awesome if you put up one of these site buttons linking back here. Also, if you tell me that you used a layout or bit of code, I can link to your site as a live demo of what can be done with the base code.
I'm making changes to the CSS on my site, so why can't I see those changes?
Check it on a mobile device. Does it look like it's changed there? Chances are, you just need to clear your browser's cache (look in your search history settings to do that). The cache is where the browser "remembers" things about the site that it doesn't think it needs to check every time.
What browser did you use to make this? It looks weird in my browser.
Google Chrome, and yeah, I don't test in any other browsers, because I'm lazy. You try figuring it out. Web design builds character.
Whoa, what's up with that Lorem Ipsum text?
Sagan Ipsum. It's cool.
So where do I go from here? How do I customize or add [insert feature here]? I still don't get this stuff.
I'll just point you at Google and W3Schools, which are really the only tools I ever used to make these. That and using "inspect element" on real websites.
These suck. You suck at web design.
Haha, yeah. I have no idea what I'm doing. But nobody else was doing something like this, and here you are. If you really think these suck so bad, make your own! I don't mean that in a passive aggressive way, either. In an encouraging way. PLEASE be better than me so I can enjoy your cool sites.