How can I know? If I am doing meditation right or wrong.

I use an app that guides me, but meditation can be many different things: even just focusing on your breath is meditation.

Try a dedicated meditating app like headspace or find tutorials or join a class. To answer your question though it's all about concentrating on yourself entirely.

There really isn’t a right or wrong way. Check out Headspace, there are free guided meditations that help you get accustomed to meditating and developing it as a habit

Focus on one thing, like your breath, or imagine the sound of the ocean. Other thoughts will come, observe them, and move back to your focus point. Refocusing thoughts is one of the powerful effects of meditation, if you are the master of your thoughts like that, you're doing it right.