How to close apps on the lenovo A516?

I have just bought a new lenovo A516 and since i used apple till now i have no idea how to close the apps on this mobile
anyone knows then please help!

Once you enter in any apps, just click left button in that phone ( or see the image) …
Click left button---> options ( it will shows some options in that logout options will be there and you can click it )
Thats All, U come out from the Apps