LaroTaio
Divide the LayoutWidth or LayoutHeight by "2" , which will put the 'Sprite' object based on its "origin point" in the center of your layout, like this:
Sprite | Set position to (LayoutWidth/2, LayoutHeight/2)
Note: if your origin point is in the center of your object, then the object's center will be aligned with the layout's center. If your origin point is in the top left corner, then the object's corner will be aligned on top of the layout's center.
Here's what 'LayoutWidth/2' means: if you folded a piece of paper from the left edge all the way to the right edge and unfolded it, you'll get an vertical crease exactly in the middle of the paper with two equal left and right halves. You're essentially finding the layout's exact middle point along the x-coordinate (width-wise).
Here's what 'LayoutHeight/2' means: if you folded a piece of paper from the top edge all the way to the bottom edge and unfolded it, you'll get a horizontal crease exactly in the middle of the paper with two equal top and bottom halves. Now, you have the layout's exact middle point along the y-coordinate (height-wise).