What I found when starting a page on William Main Doerflinger was that moderators may be experts on Wikipedea but not on the subject in question. I got a rejection, at first, with a curt "not famous enough". My immediate reaction was amazement. His son has an entry and from my "bubble" totally out of proportion to his father's status.

Fortunately I persisted, listening to sensible moderators' comments, and with threads in this parish. That's when Tony Rees (thankyou) noticed and did some fettling on the WMD page. That's the point, anyone can add so it could happen that someone else changes your additions, so be sure of your data.

FWIW I often find pages when searching, say villages, where I can add an external reference to. In some cases, links to my own websites where there is a connection of interest. Two I do regularly are an audio memories of old Stroud where I can target the particular village. Ditto benchmarks.mister.red or Milestones/Boundary Stones (particularly now in Lock-Down).
The way I do it is to: log in, "edit", look at similar things, copy, paste, modify. And each page must work similarly, because there are multiple methodologies, IME.

BTW Wiki uses "an" HTML but it is not like any other I have come across. But it is my way of thanking Wikipedia.