Each piece was well marked and the directions were clear.  I put it together myself, without help.  It was time consuming but not difficult.  I assembled it in three sessions.
The day bed and trundle are sturdy.  The bed slats are installed using plastic pegs inserted into a metal frame so they cannot slide around.  The fabric lies smoothly and the seams are nice.  Color is consistent on all the pieces. I have not added a mattress to the trundle yet.  I purchased the 6" Firm Memory Foam Mattress to test it out.  I will order another one.