There is no need to reinvent the wheel here, since this template comes with a character with scripted functionality for movement, we can copy that into our Paper Character to provide movement for it.
Inside the ThirdPersonBP folder in the Content Browser, open the Blueprints folder then the ThirdPersonCharacter Blueprint.
Inside the Event Graph, copy the Movement Input section by Left Mouse dragging a selection box then pressing Ctrl+C to copy.
There is other script in here for 3D gameplay such as manipulating the camera, controller input and jumping. For the purposes of this tutorial we are only concerned with general movement.
Return to your Paper Character Blueprint and press Ctrl+V in the Event Graph to paste it in.
Also inside the ThirdPersonBP and Blueprints folder, open the ThirdPersonGameMode Blueprint.
Under Classes, change the Default Pawn Class to your Paper Character (TopDownCharacter).
This will set our Paper Character as the default character to use during gameplay.
Inside the level delete the Blue Character so you will not take control of it when launching the game.
From the Main Tool bar, click the Play button to play in the editor.
Although the 2D character is idle, you can now move around the default map using the WASD keys.
This tutorial illustrates how to set up the foundation of a top down game by creating a playable 2D character, there are other tutorials you can take a look at to continue to develop this sample such as the Setting up an Animation State Machine (to set up different Flipbook Animation states for the character to use) as well as the section on Paper 2D Tile Maps to create a 2D map. Want a fixed camera position instead of a follow camera for your top down game? The How to Use Cameras in Blueprints page will show you how to set that up and more.