This is a good question and your observation is correct. Africa is a continent and Islam is a religion. This request might sound odd at first, but if you think about it, it does make sense. It is similar to asking a person to compare American culture with Christianity. You can say, generally speaking, American culture prizes the individual, but that Christianity prizes the importance of the group. In this way, Christianity offers American culture a critique.
In light of the above example, you can ask what things Islam stands for and ask whether it fits within an African worldview. To be sure, Africa is not monolithic at all; there are many countries, but meaningful comparisons can be made, if you focus on a few details. Here is an example. African culture is polythesitic by nature and very tribalitic. Islam believes in only one God and is not tribalistic. This can be a good point of comparision.
Some reflection will give you more insight.