Box for my Mini Avy

[smoothrunnings]

I am trying to figure out a way of building a box that I can put over top of my avy mini and put it outside on my balcony to mine. It still winter where I live and the temps are in the minuses centigrade, so I not sure which I should do with respect to building vents as I don't want the rain or snow to get into the box as that would detrimental to the avy.

Has anyone done this before? I am looking for ideas. I thought about initially buying a box and covering it in plastic, but as for the vents I am kind of lost on what I should do.

Thanks