Gotcha: Tables cannot be created during page creation. You can save the newtable code in the new page, but the table won't get generated until the new page has been saved, re-opened for editing, and then saved again.
To create a new table, you just need to define a series of column headings, like so:
<newTableEdit> Heading1 Heading2 Heading3 </newTableEdit>
Once your table is created, it can be updated by using the "edit table" link, which appears in the last row of the table.
Here is a table you can play with. If you break it, feel free to delete and start again.