I would like to know the stages of how the universe would end and what would happen and what the possible scenarios are.
I understand that eventually all the stars would burn out and that would introduce a big freeze that would make it harder to sustain life. Forgive me if this is incorrect as I do not have any expertise in this area, I would appreciate any information on this.
Adams & Laughlin wrote a great book about this, called "The five ages of the universe". It follows the history of the universe from the big bang to more than $10^{100}$ years. So the "final days" become rather longer. The book assumes the universe will continue to expand forever and follows the future of matter and energy. Up until around $10^{14}$ years (10,000 times longer than current the age of universe!) the universe is dominated by stars and other matter, as well as black holes. After that, protons that have not yet fallen into black holes will eventually decay. Later still (between $10^{40}$ and $10^{100}$ years) black holes will evaporate, and eventually we end up with an extremely dilute soup of electrons, positrons and photons that slowly drift further and further apart. The distance between any two particles will be far greater than the size of the current observable universe.
The book is a bit dated now as it did not take into account the existence of Dark Energy. Depending on what happens to Dark Energy in the future, the sequence may speed up or down. In the extreme case, Dark Energy may even tear matter apart.
