Saving and Loading UE4 Data with Blueprints
Saving your Game with Blueprints covers the basics, but it doesn’t cover how to actually trigger the save (e.g. quick save or quickload).
The variables you need:

The full MySaveGame blueprint flow for saving and loading, by triggering events:

Triggering custom events within other blueprints from an existing blueprint - because you won’t have access to the KeyInputs from the MySaveGame blueprint (they’re only available for Actors, but the MySaveGame needs to extend from SaveGame):

If classes or events are not showing up, make sure that you hit “Compile” every now and again, so that these classes and events can be picked up.