How to comment on a blog

I have had a rather lot (relative to the hits on this blog) of people asking how to leave a comment. I have answered everyone who asked directly, but thought I'd also reply here in case there are other readers who have the same question. There are two views on this blog. One is "main page." On the main page you can see the most recent blog posts all at once by scrolling down. (The really old ones have to be accessed either by "category" or by archives - see blog's sidebar.) The other way to view