Question: the six strings of a guitar is called "a set of strings".
Answer: --> The six strings of a guitar is called "a set of strings".

Question: so we can tune our brains to the same wavelength as that of the earth.
Answer: --> So we can tune our brains to the same wavelength as that of the earth.

Question: the fishermen’s recipes provide the ultimate local flavour, notably the fish soups and the rice and razor clam dish.
Answer:
--> The fishermen’s recipes provide the ultimate local flavour, notably the fish soups and the rice and razor clam dish.