Widget layout in GridLayout

[Dato0011]

Hello
I'm just making my first steps in qt so don't laugh
I want to control widget's alignment which is in gridlayout's cell. the problem is that when I place a widget in the layout, it is positioned in the center, vertically and horizontally. How can I change it's position, for example to top, bottom, left, right etc.? See the image in the attachement. The button "Centered" is in the center of the cell, I want it to be on the top. How can I achieve that?
Thanks