inner cables generally come as a set length that you feed through your brake levers or shift levers and then cut off the excess at the end after it goes through the component, which is then usually capped and crimped so it doesnt split and unwind. as stated above cable housing is sold by the foot, if you dont buy the recommended cutter you should just bring in your old housing to the LBS and have them cut it to the same length (assuming u want it to be the same length as before). from there you basically want to set it all up with little to no slack, you tube will be better for this part so you can SEE how to do it all. good luck and have fun.