Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Jakarta to Ghana as you normally would.
These are just IATA (International Air Transport Association) codes. They are used in aviation to identify and differentiate airports. That’s why a Jakarta Soekarno-Hatta Intl Airport to Accra Kotoka Airport flight would often be abbreviated as a CGK to ACC flight. Kumasi Airport (KMS), Tamale Airport (TML), Takoradi Airport (TKD), Sunyani Airport (NYI), Wa Airport (WZA) are other airports near this flight route and their unique identifiers/IATA codes.