It's a direct translation of "Do you understand?" and is commonly used in various contexts, such as:
* Asking for confirmation: "Ты понимаешь, что я имею в виду?" (Do you understand what I mean?)
* Explaining something: "Ты понимаешь, как это работает?" (Do you understand how this works?)
* Expressing frustration: "Ты понимаешь, насколько это важно?" (Do you understand how important this is?)
The phrase is very common in everyday Russian conversation.