For anyone who has a play with this tutorial -
This little trick worked for me by chance.
if you have trouble getting your BP_FPSCharacter to be GameMode Default Pawn to play correctly and for the in game message ( We are using FPSCharacter ) to be displayed.
I had to click and Drag the BP_FPSCharacter from the Content browser into the editor.
Press play and the message will display.
I then Saved and closed the Editor.
Upon re opening the editor and clicking the play button I now had the message displayed Twice.
I deleted the BP_FPSCharacter / Capsule etc, I dragged in from Content and then it worked correctly & ready to add the axis and action mappings for Input etc.
So Hope this helps someone.
And Hopefully no more issues with the rest of this Tutorial…
NOTE: It says for version 4.11 and I am using 4.13.2 so something may have change not sure.