Thanks for asking! We fully support using your keyboard to control the on-screen remote feature. If you place your mouse over each button, it will show what you need to press on the keyboard to make this function happen.
This article will further explain this:
If you have any other questions, feel free to respond or call us at 1-877-467-5464. We are open seven days a week, from 10:00am to 10:00pm EST.
The Sling Media Moderation Team