Just follow the instructions below.
How does that work you may say?
Simples. Salt lowers the freezing point of water. Normally water freezes at 0 celsius. The addition of salt will lower the temperature at which water freezes so that the salt water solution is still a liquid below 0 celsius. This effect will work for several degrees below the normal freezing point of water. So, this is why you put salt on your driveway in winter and the ice will melt, because the freezing point has been lowered.