Help please triple monitor stand

That's not entirely true, because there are several different sizes of VESA mount, and you also have to consider the weight of the monitor(s). However, the Newegg specifications indicate the Asus VH236H has 100mm x 100mm mounting holes, and the stand supports both 75mm x 75mm and 100mm x 100mm mounting. The Amazon description doesn't give the weight limit for the stand, but this page does:
http://www.outletpc.com/wq7222.html
It says 22 lbs each, and the Asus VH236H is only 12.13 lbs, so that should be okay too.