How do I access my MacBook Air remotely? (When it is in sleep mode)

Good day and Merry Christmas!

I am trying to use Screens (iOS app) on my iPad Pro to remotely access my MacBook Air to run a few OS X apps. When my MacBook Air is awake, I don't have a problem. However, I want to access my laptop when I travel for work. What settings do I need to enable to allow my iPad to access my laptop?

Also, if there is a better app to make the process easier, I am wide open to suggestions.

Thanks!