Cessationism and continuationism are two different beliefs about whether or not certain spiritual gifts, like speaking in tongues or divine healing, are still active and present in the world today.
Imagine you have a box of toys, and some of the toys are old and broken while others are new and shiny. Cessationists believe that the old, broken toys (spiritual gifts) are not available anymore, like a toy that doesn't work anymore because the battery is dead. They think these gifts stopped being given out and available after the time of the Bible, and they believe this because they think the purpose of these gifts was to help spread the message of Jesus during that time period.
On the other hand, continuationists believe that the shiny, new toys (spiritual gifts) are not only still here, but are given to people today just like they were given to people in the Bible. They believe the gifts are still important and relevant today, and they argue that these gifts help build the church and bring people closer to God.
So, it comes down to whether someone thinks that the old, broken toys (spiritual gifts) are no longer available because they are no longer needed, or if the shiny, new toys (spiritual gifts) are still being given out because they are important and helpful.