A person will first earn his Private Pilot Certificate, which will give him the privileges of flying alone or with family and friends in good weather. A Private Pilot is not allowed to fly for compensation or hire, to fly in and out of clouds or fog, or in areas of very low visibility. This means that the pilot is limited in some of the things they can do, mainly due to safety-related reasons.
The next certificate you will earn will be your Commercial License. This allows you to fly for hire, and it requires a good deal more flight time. The Kenya Civil Aviation is looking for is more experience. They expect you to demonstrate mastery of the aircraft and, therefore, require you to perform to stricter parameters than what was previously required as a Private Pilot. Now you will be able to fly for money!
If you are looking for airline or charter employment and have done all of your training in a single-engine airplane thus far, you will want to get what's called a multi-engine add-on. The requirement here is the ability to fly to Commercial and Instrument standards in a multi-engine aircraft.