1. I cut a ply wood (FREE) for the seat to the length I needed (to fit between the shelves). The wood was 1.5 inches thick and 9.5 inches wide (that's how I got it...nothing special).
2. Then I wrapped it like a present with batting (which I already had-FREE) and scrap material from a previous project (FREE). I used my staple gun to tack it down.
3. I already had the wood for the legs. They were reclaimed from a previous project. They were previously 4x4 fence posts (I had used it as legs for a short kids table for a party).
4. I cut a piece of ply board (1/2 inch tick-left over from another free project)
5. and screwed the legs to the board.
(I hope you can see it below the legs of the bench...
that brown part sandwiched between the seat and the legs).
I did it this way because I wrapped the seat first (yes, on purpose).
I needed the legs to be as far out as possible for balance, so I had to attach it last.
6. Then I screwed the plywood piece to the seat section.
I'll probably end up painting the legs to match the girls room...
...when I kick it up a level.
For now...it's functional so it works;)