Primate - You could easily occupy a couple of days or more reading pprune on flying in Africa in general or specifically on work in Africa for low time pilots. Maun is one of the major places for the latter. As all the posts say you should turn up with all the certificates, documents and records you presently posess and then some including multiple certified copies.
Operators will guide you on obtaining local licences, the requirements of which will vary from country to country or even place to place. In some places it may require little more than attending the nominated location with the readies to convert your FAA certificates to local certificates. If you are serious about Africa spend time reading pprune, contact some of the businesses to let them know you exist, get your documents together then go and knock on doors.