Previous means the one that just came before. For instance, the previous sentence explained the meaning of the word previous.
With previous, you first see that the prefix pre meaning "before." The second part of the word, vius, — think via — means "road," so you’re talking about the road, or thing, before. Previous, though, can be used with people, or anything else too. You will know right away if the previous tenants had cats. Do you ever wonder what you were in a previous life? Rivers are at flood stage from the previous two rain storms.