Cells are separated by spaces. If you want a space inside a cell, use @. If you want an @ in a cell, you have to edit it in manually. ;)
Use <^> to specify alignment, with < as the default. The alignment string is repeated as necessary, so if the table has 6 columns & you want <><><> alignment, you only need to type <>
The table is formatted to look nice in the Markdown. i.e., each cell in a column has the same width, and is aligned correctly.
There's a button to copy the table to the clipboard.