Each row of the table list describes one table. If a row has a lighter background, you are able to join it. Generally, these tables can be found at the very top of the table list.
On the far left of the row, you can see the number of rounds, and to the right of that is the number of players.
After that, there are the profile pictures of the players who want to play at this table or some text if there is no one else sat at this table.
On the right, there may be symbols for prerequisites and playing conditions for the table. Click here to find out more.