1) The buttons should not be on each panel in the CardLayout. They need to be on another external panel that is always visible, regardless of which card is showing on the card panel.
2) Once your buttons are located correctly, you would add an ActionListener to each, whose actionPerformed method would look something like (using SIM button as an example):
CardLayout cl = (CardLayout) cards.getLayout();
cl.show(cards, "SIM");
Further reading: How To Use CardLayout
EDIT: In theory, you could have the buttons directly on the card panels, but it would be the opposite button on each panel (i.e., the SIM button would be on the Help panel, and vice versa).