How to make the menu in the mobile version collapse on click?

Question

Bootstrap

I have a one page wordpress website. In the mobile version, when you click on a sandwich, a menu appears on the left, but when you click on a menu item, it does not disappear by itself. How to make him do it? I really need your help ... In this I can say a beginner ... there is basic knowledge, but no more. What and where to edit?