When installing cpanel does it not work it out for its self? and optimize it? or do I have to do this?
There are things that are down "out of the box' per se that help with optimization but it is best to tweak a few settings to get even a little more out of it. Do you happen to be a managed provider? If so, they may be able to do this for you and if it is something you want to learn, they should be able to allow you to do it but assist you along the way.
██ KVM SSD & SATA VPS | Dedicated Servers | Colocation
██ Managed and Self Managed Servers | North Carolina, Washington D.C, London and Texas Data Centers
██ www.bigbrainglobal.com | Big Brain Global Networks
There is a really nice wizard of optimizing the server right afte the setup is complete.
If I remember right, the only think you shluld change is the DNS servers names, everything else will be ready for you.
If you want further costomization, there are planty of information in the Internet as cPanel is the most popular one in the world, so google is your friend ;-)