on what procedure a telegraph work?

Answer 1

Morris code was the system used to harness the signal-sending abilites of the telegraph.

Answer 2

A telegraph system consisted of a power supply and at least two electromagnets and two switches. The electromagnets has a mechanisms which would be attracted by the magnets, making a clicking noise when they were attracted, and a different click when they were deenergized. The switches were called keys. They were spring loaded. When they were depressed they opened the circuit. When they were released they closed it again.

A rest, the electromagnets were energized. Each time a switch (key it was called) was momentarily opened a double click occurred. Morse code was a method of grouping clicks to form alphabetical letters. If the key were held down for just an instant, the clicks were close together. This represented a dot. If the key were held down for a bit longer, the clicks were farther apart, and represented a dash.

Do an internet search on Morse code alphabet to learn the code.