The classic approach is from Chitimba on Lake Malawi, up a steep road with a series of hairpin bends. A high-clearance vehicle is strongly preferred, and in the rainy season you should ask locally before attempting the climb.
Hiking from the lakeshore is possible and memorable, but it is a serious ascent in heat and humidity. Carry water, start early, and consider breaking the trip with a stay near Manchewe Falls or one of the escarpment lodges.