I’ve attempted my first Wiki edit, adding a birth date to an entry. I’ve got a reference ([sup][1][/sup]) by the date, but it doesn’t link to the reference. That is, I have <ref>[referenced text],</ref> after the date. Below, I have :
==References==
{{Refbegin}}
- [the reference]
{{Refend}}
How do I make the [1] link to the reference?
You’re basically combining two separate, noncompatible ways of doing references. The <ref> tag is part of the Cite.php MediaWiki extension, which does a lot of stuff automagically. {{refbegin}} and {{refend}} are a manual way of doing the same thing, but are less useful in that they don’t bother to look for <ref> tags in the article body. To fix this, just change that references section to simply:
==References==
{{reflist}}
Oh – Suppose I want to include a link in the cite?
That’s fine, just put it in the <ref> tag. Basically, whatever is in the <ref> tag gets regurgitated later in the references section. So, for a really simple example, you could do <ref>[http://straightdope.com The Straight Dope]</ref> (The single bracket enclosure there means, the first “word” here is a URL, and the remainder is the text of that URL.)
If you’re feeling more adventurous, you can also use a template called Cite web, which pretty much just takes what you tell it about your citation and puts it in a nice pretty format. Cite web has two required parameters: url and title. So you could do <ref>{{cite web|url=http://straightdope.com Straight Dope}}</ref>. It also has a number of optional parameters, listed in its documentation at Template:Cite web - Wikipedia So an even more complex example could be <ref>{{cite web|url=http://straightdope.com Straight Dope|accessdate=2010-01-22|first=Cecil|last=Adams|publisher=Chicago Reader|month=July|year=1988}}</ref>.
Finally, I’d like to mention that you can name <ref>s, and reuse them later. So if you’re citing Unca Cece a bunch of times, your first cite looks like <ref name=“straightdope”>{{cite web| … }}</ref>. Then, following cites of that reference can be only <ref name=“straightdope” /> with none of the rest of that mess.
Note that when I’m trying to learn how to do something on a Wikipedia page, I find it useful to look at the code for a page doing something similar, and then copying the formatting. Another thing that’s useful is to set up a Sandbox page. You can set one up as a user subpage and then leave it open as long as you need to edit your page and get it ready for prime time.
Thanks again.
I’m not feeling too adventurous, as this is the first time I’ve tried this. I just looked at the source and mimicked what I saw. (I did see the links made the way you said, but I didn’t try it because I didn’t know how it worked until you explained it. I have the reference linked now.) If I’m feeling adventurous mañana, I may add an Info box. 
EDIT: Dewey Finn. That’s what I did (though I didn’t go to the sandbox). 
.
I copied some code to add an infobox, but it’s not showing up on preview. What am I doing wrong?
{{Infobox Historian
|birthdate = {{birth date and age|1929|10|31}}
|birthplace = [[Bauxite|Arkansas]], [[Arkansas (U.S. state)|Arkansas]], U.S.
|spouse = Melody Webb (1982?-present)
|occupation = Historian
|yearsactive = 1957 – present
}}
Hm. Apparently ‘Historian’ is not a valid infobox title. On a hunch, I replaced it with ‘Actor’ (which he isn’t) and the box came up. So I tried ‘Person’. Only his occupation and spouse came up. No birth date and age, no birthplace.
Here’s a list of people infoboxes. As you noticed, historian doesn’t exist, although “writer” does.