It's like saying "you know" in English. It is used in a variety of contexts, including:
* Asking a question: "Sabes dónde está el baño?" (Do you know where the bathroom is?)
* Making a statement: "Sabes que te quiero mucho." (You know that I love you very much.)
* Expressing uncertainty: "Sabes, no estoy seguro." (You know, I'm not sure.)
The form "sabes" is used when speaking to a singular person, while "saben" is used when speaking to multiple people.