how do you use an app that you downloaded on your computer?

How do you use an app that you down loaded on your computer. I am having trouble because I can download the app just fin but when I actually want to use that app I have no idea what to do. I tried to look for any open buttons but there are none. I downloaded the app on my phone origionaly and I then I downloaded it on my laptop. the app is called arkvpn.