whats the correct placement of coolant hoses from heater and overflow tank at the block

replaced oil cooler, and head gaskets, after finding oil in coolant. only have water in the coolant system, and its overheating, boilong back into overflow tank. I'm not sure I have the resevoir hose and heater hoses in right places. all three have similar inlet size, and I have replaced the hoses with generic tubing...there is one on the cross over housing, and two at the lower radiator inlet. I'm thinking one of the two goes to overflow and one to heater, cross over attaches to heater. new water pump, and the fans work.