The dash items are illuminated by miniature bulbs mounted in plastic holders which fit into the back of the instrument panel. These bulb holders have a rib on the end which serves as a gripping point; and they can be removed from the panel by turning them 1/8-1/4 turn counterclockwise. The bulbs are commonly sold at auto parts stores; but you'll need them to look up the correct bulb number for your vehicle year and model; unless you find the bulb number in your owners manual.
It can be a major pain to access the back of the instrument panel; it often requires removal of the panel mounting screws, and pulling the panel out a few inches toward the driver's seat. It then may be necessary to disconnect some or all of the wiring harness plugs which attach to the panel (which often are secured by tricky wire or plastic latches). The speedometer cable may also need to be disconnected to allow the panel to move far enough out to access the bulb holders.
If you are not mechanically inclined; or have a low frustration tolerance; I would not recommend trying this yourself.