How do I step on two arrows at once? My Pad wont allow it

Just as the title says. I would love to be able to rest one foot on the left arrow (lets just say) and then hit the up arrow with my right foot and I can't do that. Because it no longer recognizes any of those arrows. Its quite confusing.

What can I do to solve this?
I have DDR Universe 3 Dance Mat From Konami for the Xbox360
And just downloaded StepMania 5 Beta 3? Something three.

Please if you know an answer please explain with great detail, and even explaining things that should be a "given" I'm AWFUL with computers.
I have no computer common sense.

Thanks Again :)

Pierson

Install XBCD and bind the arrows to buttons instead of a D-Pad.