Use a node called CharacterBody2D.  
This node has functionality built in, such as  
physics and the ability to detect collisions. 
Add a Sprite node as a child 
Use the Player.png as the texture 
Rename the CharacterBody2D to Player 
Rename the Sprite2D to Sprite 
Add a CollisionShape2D as child of Player 
Add a rectangle shape to it. 
Cover the Player with the HitBox