The labelled areas in the phase diagram
These areas all show what you would see if you had a particular mixture of salt and water at a given temperature.
For example, if the temperature was below -21.1°C, you would always see a mixture of solid salt and ice. There would never be any liquid whatever proportions of salt and water you had.
At temperatures above this, what you would see would depend on where your particular set of conditions fell in the diagram. You just need to notice what area the conditions fall into.