We have made the point many times that kalimba tablature is a time map - horizontally it shows you different tines, and vertically it shows you different times. The tablature, like standard music notation, is split up into bite-sized chunks called "measures", and each measure gets the same number of beats.
A measure is like a little piece of the song's "dance". It is the same size as the natural little rhythmic fragments that keep coming around over and over. A measure and its time signature will fit naturally with the song and will reflect it's recurrent structure.
Imagine that a song will reflect a particular way of moving. That basic manner of motion may have four beats, or three beats, or six beats, or something else. The cool thing is that the music - or in our world, the tablature - will reflect that basic way of moving. It is called the "time signature", and you are about to learn all about it.