I watched this one a couple of times.
It 's a good introduction when you want to make your test project more into a game and want to add different levels etc…
UE4 Game Framework Basics in Blueprint
explains the relations between game instance and other components
in combination with https://docs.unrealengine.com/latest/INT/Engine/UMG/QuickStart/index.html
Special from step 3 creating a main menu …
And of course all the other videos and live streams!! they are an amazing resource, event for little tricks and hotkey stuff that is mentioned ocasionally