Mattress doesn't slide around!

My granddaughter is ready to sleep in a big bed instead of her toddler bed so I ordered this metal twin frame for her new mattress. The bed is plenty tall to place tubs of toys and shoes under it, but not too tall that she has problems getting on an off. (The boxes must be 11 3/4 inches or shorter) The frame is sturdy, weighted and seems well made. I had a few problems putting it together since the drilled holes didn't line up on the end bars and I had to find some thinner screws so that they would go through the uneven holes. I do like how the slats slide into place and leave a lip for the mattress to fit in so the mattress will not slide off the rail.

The bed needs assembled and arrives in 19 separate metal pieces plus a bag of screws, nuts,1 hex wrench, 1 wrench and 1 instruction sheet. First you put the 4 end legs on the outer frame of the bed together. Next I found it easier to put the middle bar on and then the end bars. After the outer frame is put together, just slide the slats into position and your bed is finished. The slates are 6 1/8 inches apart from each other.

Note: I only gave this bed a 3 star instead of 5 star because the holes were drilled wrong and that they didn't line up for the screws to fit properly. Iused smaller screws to make it work.