To choose a table from the software’s homepage you may double clicking on it, or select it and click on the red Go to table button. Once the window with the table opens, click on any available seat to join the table. Enter the amount of money you would like to have with you at the table and click on OK. When you are ready to play click on the SIT IN button and you will be dealt in the game.
At newly starting tables, to decide who will be the dealer, each player will receive a random card face up. The highest card gets to be the dealer.

Note: Besides physically joining a table, and being represented by a character, there is always the option to just watch.