Installation is pretty straightforward. Once you've purchased the plugin, do the following.
1
Open the Epic Launcher
2
Go to Library
3
Search for Distance Field Outline
4
Install to Engine
Choose the engine version of your choice. Supported version are from 5.2 to 5.5.
5
Start Unreal Engine 5
6
Enable the Plugin
Once you've enable the plugin you can either use the quick start guide, use example materials found in the plugin content folder or start from scratch.