I'm travelling on a British passport to Ghana with a Ghanaian citizenship card through the Netherlands. Do I need an airport transit visa?
As a dual citizen usually each of your citizenships can be used when you pass borders, and the Schengen area does not make exceptions for Ghanaian citizens.
So you show your British passport to the airline, (likely next to your Ghanaian citizenship card to show you do not need a visa for the final destination,) and you will be allowed on the flight to Amsterdam, and there you can just follow the signs to your next flight. (There might be security between the gates but that should be all.)
If you have a long layover in Amsterdam you can also leave the airport, as British citizens do not need to apply for a visa and will just get a stamp in their passport.
You can and should double check in the site which is mentioned in the linked question: Do I need a visa to transit (or layover) in the Schengen area?