Tuning a Kalimba is simple
The kalimba, or mbira, is a very simple instrument which can be easily tuned. Models vary in complexity and tone, but the two BrandNewNoise versions are easy for anyone to start playing immediately reguardless of musical knowledge.
The tines (or keys) on kalimbas are generally made of spring spring steel. To change the pitch you can slide these pieces back or fowards under the square bar holding them in place. You must first loosen the bar, starting with turning the two screws about a 1/4 to a 1/2 turn. You can then easily move the keys with your fingers (I wear a thimble for extra leverage).
If you wish to purchase an additional set of keys, you can follow the video for how create a chromatic scale.