Is the problem that you don't know how to remove the cluster? Did you remove the 2 screws circled at the top? Once the bezel/cover is removed then there are usually 2 screws/bolts at the top and the bottom. See circle in lower left of pic. Once you get those removed the cluster will pull out only a few inches. Then disconnect the connectors from the back of the cluster and remove it to replace any bulbs.
Pull one out and see if there is a number on it. Order from the dealer, they will know the right bulb. Most times these cluster bulbs are only available from the dealer and they are pricey, could easily be $8 - $12 per bulb if not more. Even if you could find them aftermarket I have heard that they only last a few months. As far as the needle look at the back of the cluster and see if there is a bulb for the needle in the center of the tach and speedo. If there is the current bulb is clear and changing the color of the bulb would change the color of the needle. Here is a link on painting a needle. How to Paint Gauge Needles — revlimiter.net
This place sells needles for some small trucks and International or Freightliner clusters. Buy Freightliner Instrument Cluster – ISS Automotive Solutions
A short video: (2) How to change your gauge needles color. Part 1 - YouTube
Numerous other ones online.