ASUS Remote Link is the best Android app to use as a remote control for your PC. It is great for viewing presentations and for controlling media (video and music). You can even control your PC through voice commands.

How to set up the app:

After installing the app, open it and log in with your username and password. Then, you will be presented with the list of devices you can connect to. Click on the device you want to connect to, and it will start to connect. When the connection is established, you will be able to control the PC.