This is not a step by step HOWTO. The reader is expected to first read the entire document so that he (or she) becomes aware of the possible pitfalls and performance bottlenecks. After having a fair idea as to what steps are to be taken, he (or she) can then follow the next section in a step by step manner. Since you will be playing as a root and that too with the system initialization files, be alert as to what you are doing. Write in those files comments for those sections that you added, and when you want to remove a section, do not delete it. Instead just comment it out. (In shell scripts comments begin with a pound(#) sign). In case things go wrong, you may restore your original configuration by removing the changes you did. Although you are not required to know shell scripting since I have given all those that would be needed, some knowledge may be advantageous both for understanding as well for debugging.