Asia Direct 8420 Mission style white finish wood twin size storage trundle bed

I got the one without the trundle. Wish there was more details provided for this bunk bed. When I got the delivery, that is when I found out that a bunkie mattress or bunkie board must be used with the bunk bed. Should be 75" long and 37-1/2" - 38-1/2" wide with no more than 6" thickness/ for each twin bed. Also the surface of the mattress must be at least 5 inches below the upper edge of the guardrails. I would said the rail is about 15 inches so in total, the bunkie board and mattress need about 10 inches thick.