Sweet little canopy bed!  Our daughter, who's 3 ½ years old, absolutely loves it!  It's made of a sturdy metal frame.  It came nicely packaged in one long box.  The frame took my husband and I almost 1 ½ hrs to put together.  Having two people to assemble definitely helps with this one. Pretty easy though... just follow the letter stickers and holes on each metal piece to make sure it corresponds with the piece on the instructions!
I bought a 10 inch mattress to go with this and I think it's fine for my daughter.  I would go lower if you feel like your little one might bump their head on the upper side railings while possibly standing.. or shall I say jumping?! 
Super cute and really good quality!  I definitely recommend this bed for any toddler or young child!