1993 Honda Civic overheating issue

You need someone to actually look at it to see where the coolant is leaking from. It could be as simple as a ruptured hose or loose hose clamp, or as serious as a leaking cylinder head gasket. If a head gasket is leaking, the coolant will typically be overflowing from the reservoir.

If the radiator is new, I have to assume it's not broken and was installed correctly, meaning no loose hose clamps. Steam indicates the system is not full of coolant, and that can stop it from circulating through the radiator. That alone will make the engine overheat and cause steam to come from the radiator. I'd have the person who replaced the radiator recheck their work first.

Sorry that I'm racing a dying laptop battery. I'll be back in the next day or two to see how you're doing.