Since this graph is about changing a liquid into a solid, we can see from the graph that around 1405 degrees Celsius is the freezing point of the element as it’s the final temperature recorded in the graph and so in that region of the graph, the element is a liquid. In the region where the graph is completely horizontal, a change of state is taking place because whenever there’s no gradient in a heating curve i.e, when the graph is horizontal, it represents a change in state. Therefore, from 1650-1495 degrees Celsius, the element is a gas and then during 1495 degrees Celsius, it changes state from a gas to a liquid.
In the first region of the graph, as more and more energy is being taken away while the temperature’s decreasing, the particles of the element, due to the decreasing amount of kinetic energy, start to move more and more slowly until it reaches 1495 degrees Celsius, the condensation point of the element. In that temperature, the particles of the element move a lot less slowly than in the gas state and forces of attraction start forming between them as the element changes state from a gas to a liquid. In the last region of the graph, the particles start to move even more slowly as more and more energy is being taken away until it reaches 1405 degrees Celsius, the freezing point of that element.
I really hoped this answer helped!