Preferably West Africa but not essential. I'm looking for an understanding of the changes that went on due to colonialism and the knock on effects resulting in the subsaharan Africa of today. I'm not a history student or experienced in reading historical texts so perhaps recommend more accessible texts.
The Fate of Africa by Martin Meredith is exactly what you're looking for. That said, it covers the whole continent from the colonial era to post-apartheid South Africa, so it's still a pretty big book, but very good.