Slow down movement while playing

Hi Community,

I’m new in UE and I have started my first Project with a Blank-Projekt (Unreal Browser > New Project > Blueprint > Blank (With Starter Content)).
I have build a small environment and add a Player Start so that I can walk through it when I click PLAY. I move around with WASD and Mouse.
Now my question: How can I change the velocity, so that I walk slower? There is no special character in game, just the Player Start.
Do I have to add a player-object-thing to slow down the speed of myself? Is it possible to add a player belater cuz I have started with a Blank-Projekt?
What to do?

Thanks and Greetings