I am an American that is moving to Gambia with my husband that is from Gambia.
Wow, that move sounds so exciting!
Like Daniela, the locals as well as other expats living there will be able to help you settle in. From my experience, the Gambians I met were more than happy to teach me about their culture and way of life so I wouldn't worry too much.
I've travelled back and forth there and will be making the move myself.
I wish you luck with the move! I'm sure everything will be fine.