Charakter Dont Collides Correctly With Objects

Hey, i want to ask, what i have to do the charakter collides correctly with the objects.
I created this charakter with blender.
Look in my screenshots, you can see the charakter shape there, and then you can see that the charakter always is inside of the ground plane.
And when the charakter jumps under an object, the head doesnt collides with the object, the head always comes inside the object.
It seems like there is a very small shape around the charakter.

What i can do to fix this?

Thanks.

 

Here is a picture from the collision shape, thats how i thought.
How i can change that?

 

In the top right of the scene editor click the little ball/globe icon

That will show the colliders

Make sure you select the collider you want in the object tree and then resize in the usual way

 

Yes i already saw how it works, but thank you very much.