Process Sigma Level vs Cpk vs Ppk

Confused about the concept of Process Sigma Level, Cpk and Ppk ?    This is actually quite easy to explain.   1.  Process Sigma Level and Cpk are 2 different index numbers that are used to indicate the Capability of a process to meet customer expectations with its output ( product or service being delivered by a process)  2.   Both index numbers are calculated in a similar way and use a similar simple equations…that anyone passing maths  at High School ( secondary school ) will be able to understand .  3.  Both calculations use the Standard deviation AND the Mean Average of the distribution of values in the process output ( both of which are estimated by measuring samples).   4.  Process Sigma Level turns out to simply 3 times the Cpk value where short term data is used. 5.  the 1.5 standard deviation  ‘Fudge factor’ should only be used for long term data calculations.
If you want more information on how to define and use Process Sigma Level,  Cpk or Ppk then I would like to here from you and I will be happy to answer any follow-up questions that you may have.