I'm not sure if we have a thread somewhere in the forums specific to this, but here is a quick link to an HTML table generator:
For your table, I didn't use any border, cellpadding or cellspacing. It has two columns and three rows. The width is defaulted to 100% (so you don't really need that).
Typically, a table looks like this in HTML:
So this is what all that means: the table and /table tags tell the HTML that you're starting a table (and the /table tells it that you've ended the table - that's what the slash means in HTML when it comes in a tag like that). The tr tag means "table row", and the td tag is "table data". So if you have two columns, each table row should have two td tags (with closing /td tags); if your table has three columns, it should have three td tags (with closing /td tags). So in the above example, you have two rows and two columns. If you wanted to add text or anything else, it would go inside the td tags like this:
<tr><td>Cell One</td><td>Cell Two</td></tr>
<tr><td>Cell Three</td><td>Cell Four</td></tr>
In your example, Cell One and Cell Three would have the PayPal image code, and cells Two and Four would have the explanatory text.
One last thing to mention: you should only use HTML code in the "Text" view of the editor, not the "visual" view.
I hope all that is helpful!