I assume you have some radio gear Jack, ie. a Transmitter and Receiver? If so, how many channels is it?
The ESC (Electronic Speed Control) has four wires, red, black, blue and yellow - The RED wire goes to the POSITIVE terminal of the battery, the BLACK wire goes to the NEGATIVE terminal of the battery. The YELLOW and BLUE leads go to the motor - These can be connected either way round, it won't make any difference..... If the motor turns the wrong way, simply reverse the YELLOW and BLUE leads.
The small plug with three leads goes to your reciever - If it's 4 channels or more it goes into channel three, if it's two channels it goes into channel two.
The rudder servo lead (again the one with a small plug and three leads) goes to the receiver in channel one...
Hope that helps?
Regards
Eddy
P.S. The best advice I can give is to join a local model boat club, they will guide you through all this... it's MUCH easier to see these things done in real life rather than trying to understand written instructions with the danger of getting it wrong!