Without pictures, it's impossible to answer.

My initial question is why you would want to convert to a daybed. I have a queen bed that I use as a bed and like previous posters, I can't see it functioning well as a couch or chaise which is essentially what a day bed is supposed to do - i.e. be seating during the day and then be used as a bed when needed for sleeping. In my experience, day beds are generally twin size - if a larger sleeping surface is needed, there is the kind of bed which slides out somehow.

Reread

this is for my daughter's room and we want a daybed in her room and it's a queen size bed there so many queen-size daybeds out thereon

just curious as to why you guys think that this may not work no it may not be the most comfortable thing you said on but I want it long ways against the wall for more room does that make sense?

When I was at college, I wanted a day bed look. I got a bedspread that reached to the floor on all sides, and sewed the corners so it fitted like a box over the mattress and box spring. Then I put long body pillows against the wall. It looked pretty good and was comfortable to sit on during the day as a sort of sofa.

Well, I guess it's okay if it's just kids lounging on it. As an adult, I wouldn't want it, but kids don't need back support like us older folk ;) I have to say, though, it'll be no fun changing the sheets if it's got attached backs and sides...

I want a daybed as an adult, and am trying to convert a full size metal platform bed into this. I don't understand all the questions as to why when the original question was as to how.

I guess I am on the wrong site where everyone is asking stupid questions and ignores what the OP is asking about.