As you can see, this djembe has some damage to the finish in a couple places in the form of pitting. Looks like something may have gotten under the original finish or been in the wood itself. It also needs a new skin.
A few drop fills with CA glue followed by a light sanding and buffing will smooth and seal the affected area before a new goatskin head is made ready for installation.
Once the new skin is in place the process of tuning the head begins. Over the next several days to a week the skin will dry and tighten. As it does the tuning is checked, mostly by ear but occasionally with a tuner. This is not to find a specific pitch, but rather to insure that the skin is stretched evenly and harmonizes with itself.