All you need to do is to buy a new hose, loosen the hose clamps on the ends of the existing hose, pull the old hose off the spigots (or cut it off with an exacto knife or razor blade if it will not move); clean and scrape off all traces of old hose material from the spigots, slide the new hose into position, and firmly tighten the hose clamps (use new worm gear hose clamps if the old ones are the wire type). There will probably be some coolant leakage while the hose is off. The mess from this can be minimized if you open the drain valve on the bottom of the radiator and drain the coolant into a container before removing the hose. After the new hose is installed, turn the heater temperature control to hot (in order to allow coolant to flow through and fill the heater), remove the radiator filler cap and pour a mixture of equal quantities of distilled water and new coolant directly into the radiator, until the radiator is filled to overflowing. Then start the motor; the coolant level will drop when the motor runs; so while the motor is running, refill the radiator to overflowing again, and install and tighten the radiator cap before shutting the motor off. This should be done before the motor has run for more than about 3 minutes; as it will begin to heat and expand the coolant after that. It is often a good idea to replace the heater hoses, and possibly also the main radiator hoses, when the bypass hose goes bad. So I would carefully inspect all the hoses and their clamps before deciding what to buy. The coolant overflow reservoir should also be filled to the proper level with the same 50-50 mixture of coolant and distilled water at this time.
The day after doing this repair; remove the radiator cap again, and check and refill as necessary the coolant level in the radiator with the motor cold and idling . There is often trapped air that will come out of the system, which will cause the coolant level to drop. Only after the air has all come out of the system can the level be trusted in the overflow reservoir. If the level was significantly low, recheck it again on one or more subsequent days; until it stops dropping; or until the source of any additional leaks is discovered and repaired.