There are several ways to get to the Cashier from the Poker Software:

1) If you click on a Real-Money game on the Lobby, and don't have enough for the buy-in, you'll be asked if you'd like to go to the 'Cashier'.

2) On the Lobby Screen, click the 'Cashier' button on the lower part of the Lobby Screen.

3) At the Poker Table, right click anywhere on the table for a menu that will allow you to open the Cashier page. You can also click the 'Get Chips' button found on the lower right of the screen, this will lead you to the Cashier.