How do I make a persistent navigation sidebar across my pages?
How do I set up a blog on my site?
So both of these are great questions that come up a lot; but they are also hard to answer becouse there are BILLIONS of ways you can do these and none of them are the right or wrong choice; its just about finding what suits you best. Of course if you're just starting out you don't know what suits you best; so I would actually suggest trying a few options and seeing how they feel.
For the Nav BAR:The simplest way is using frames or iFrames - the absolute simplest is using Frameset (you can look at my homepage to see a typical frameset style site) - we actually have
a guide on the wiki here for this.
You can use also iFrames for a more modern look, but requires you to put the iframe on every page correctly. In this case; you just make your nav as a separate html file, then put an iframe on every page showing that same nav page.
(We should really have a proper guide on the wiki!!)
An alternative iFrame system is to have a main content iframe, and a nav iframe both on one single index page (this is actually more like frameset - A well known site using this layout is cinni.net!). The benefit here is that you don't have to duplicate the iframe on every page; but it can also cause some layout issues.
(If you need help with a particular one just ask and Im sure you'll get more specific advice!)
After that you can use JavaScript to load your nav (I don't recommend this). Or you can use a static site generator as akesi says (but if your asking this question, then I don't recommend that as its a big learning curve and not well suited for everyone, particularly beginners)
As for Blogs:Yep, the simplest way to start is just to put text on a regular HTML page; if you find you like blogging (say you've done about 10 pages/blog posts), then come back and ask again because you'll be in a better position to know what kind of blog you want! (There are MANY options for more complex blogging platforms)
Where can I find good resources for geocities-style images and gifs?
I link a few on my
website guide; but one I forgot to add there is
GifCities
Also to answer your more over arching question... honestly this is one of the best places to ask (along with some of the Neocities discords that exist) - the thing is there are just not that many resources actually dedicated to homepage creation - so you can get lots of tech help; but for actual homepage questions, most of us learn from copying each other or asking in groups like this!