Moving to Germany after merriage

Of course you do not need a visa to live with your husband in Namibia.
If you want to move to Germany with him, you need to apply for a family reunion visa at the German embassy. You need to show sufficient financial reserves (€8300/year per person), living space (e.g. rented apartment for two people) and health insurance for both of you. You also need to have basic German language skills, although you can also take the compulsory cultural integration classes after arrival in Germany instead.

Apply for Family reunion visa in your country, it takes roughly 6-8 weeks, then once you arrive here in Germany you can go to Landratsamt to make Resident permit, but first,you have to go take care of other papers like insurance,family book,residential address,re Register your marriage in Germany etc.

Goodluck.

Hi

Try to learn as much German you can, at least B1 by Goethe Institute.
For administrative part your fiancée can find out more from embassy or migration office in Germany .