It might be fair enough to expect that an explanation on the feast called All Souls day would have some explanation of the concept of Purgatory. So Here is an explanation from my favourite reference Defend the Faith from Lumen Verum Apologetics. They have weekly talks that I wish I could attend. A great source of guest speakers too, for all your Catholic faith building meetings.
So for November, month of the Holy Souls, we visit a cemetery. Any will do. It would be good to visit graves of our loved ones, maybe next time we’re in Sydney. Also many have been cremated instead.
You forget how peaceful it can be to visit a cemetery. Even with four boys running around there’s a chance to be solemn. Remember this life is only the trial run for eternity. This mortal life has an end. As long as the days seem sometimes it will come to an end. Fight the good fight while you can. Pray for a good death.
The other thing to see is there is a Someone who made these souls, who will not forget/annihilate them. In life we can chose to serve things like money, or people, or God. Once we start looking for what is best, God will draw us on to the Truth.
And the Truth will set us free.