[UMG] how to properly use "Grid Panel" widget?

thank you for answering!
howerver, it doesn’t seem to work like i’ve described above, instead it arranges the stuff pretty similarly to uniform grid, for example:

140189-screenshot_2.png

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here the small widgets (button in this case) takes a place of the biggest widget in it’s row and column, and i can’t figure out how to put a lot of small widgets there instead of one (because there is simply place for them)

do you have any clue?