Knowledge creation can be confusing. One could think that knowledge creation is the creation of knowledge not yet created or understood. Knowledge is defined as a person's understanding or familiarity of something. Creation is defined as the making or invention of something. Therefore, one could define knowledge creation as a person's understanding/familiarity of making or inventing something.
Instead, knowledge creation is defined as the combination of the known and unknown (possible) ideas within a human's mind. What the unknown refers to is the information stored within a human's mind which has yet surface.
One visual symbol of knowledge creation is an ice burg. When observing an ice burg at water level, one is only able to perceive a fraction of the ice burg. Much of the burg is actually hidden under the water. In this metaphorical example, knowledge creation is the information which lies below the water level (the hidden part of the burg).
Sometimes this information is difficult to bring to the "surface" given one lacks the ability (or knowledge) in regards to how to do so. It is the knowledge one possesses in how to bring the knowledge to the surface which defines knowledge creation.