Try & start with PC Maintenance and Servicing from the University Of Zimbabwe Computer Centre. You can also further your knowledge with Data Communications & Networking, Linux Administration,Linux Security &Services, Windows Server Administration,Oracle DB Administration and so on. all these are available at UZ.
Should you want to beef it up then Go to McMaine School of computers after UZ studies & get a diploma or hnd of the equivalent courses.With these you can start your own SMB or work as an IT tech or admin.With expirience you can be a good IT Engineer.
Cheers