I use 1/2" barbs and silicon hose....but to answer your question,
the march pump head is 1/2" MPT (male pipe thread). So you need on the inlet to the pump at the very least a 1/2" female pipe thread to 3/8" hose barb. On the outlet of the head you need a coupler (1/2" MPT coupler, ($5 for SS see bargainfittings.com)), a ball valve (for pump control), and a 1/2" MPT to 3/8" hose barb, and a couple of hose clamps (for both barbs).