I was asked once how I put tables in posts. I answered in a comment written hurriedly, and if you were not following that discussion, you never saw it. Here is a clearer explanation:
I write my HTML by hand, which gives you what you want, as long as you use the proper symbols.
This is my generic table, with the angle brackets, "<" and ">,"
replaced by square brackets, "[" and "]."
You start by declaring a table, and saying how the outline should look:
[table border="2" cellpadding="8" cellspacing="2" width="100%"]
You continue with the information. I'm assuming that you want the same number of boxes -- or "cells" in every row. You start a row with [tr][td]. "tr" is a table row; "td" is table data -- what you put in a particular row. You put "[/td][td]" for one fewer than the number of cells you want in each row -- that determines the number of columns in your table. This row has ten columns.
[tr][td] [/td][td] [/td][td] [/td][td] [/td][td] [/td][td] [/td][td] [/td][td] [/td][td] [/td][td] [/td][/tr]. You always end with [/td][/tr].
Then you copy and paste this blank row for as many rows as you want in your table -- including the headers.
Then you put the data in each cell. "td" stands for "table data." The data for each cell comes after the "[td]."
Finally, you close the whole thing out.
This is how such a table with three rows looks:
For tables on dKos, most of those numbers I put in don't seem to matter.