How to make dashi if you have dashi chunks

First clean the dashi chunks. Divide it into two or four petals. Washed and put in a jar with water until submerged, pour out the water. Three pounds of water and a catty of water ratio of salt and open and leave overnight. The next day the above clear salt water poured into the sauce jar, ginger must be submerged. Use a stone to press the sauce block floating on top. Salt water is best bought Boomerang concentration meter to measure the concentration of 19 ~ 20 degrees. Put in a cool place to ferment for more than half a year.