John, thanks for the star. I think they call all the tags and such here "Wiki mark-up." What it equates to in my estimation is very basic html which we used to use back in the early 90s to build webpages.
If you want to use inline citations, that's great. If you don't, you can list your source citations below the == Sources == and <references/> down at the bottom. If you choose to do that, you will not be using <ref> and </ref> tags at all. Start each new citation with a * to give it a bullet to make it look neater and so people can tell where one source ends and the next begins.
If you do choose to continue to use inline citations, one way to make sure you will always have matching tags is, when you are ready to insert a citation, click on the C in the edit text (above the bio editing box.) An automatic <ref></ref> will be placed. Then you just type (key) your citation between the two tags so it begins with the <ref> and ends with the </ref>
You can also mix your type of citations. Sometimes you may want a particular source to go with a particular fact. That's when you'd use an inline citation. If it's just a general reference and doesn't go with a particular fact, you can place it below == Sources == and <references/> in a list as I explained above.
This page on Sources may be helpful for you.
If you learned Basic and Fortran back in the day, I know you'll be catching onto this quickly. All the best!