You will need to remove the top cushion and seat then mount the folding bed frame to the inside of the ottoman. Test the installation to make sure the bed will unfold and setup normally. Mount the ottoman seat and cushion to the base with hinges to give access to the convertible twin bed.
A pair of Mission style oak convertible twin bunk beds. This bed features a thick rectilinear frame, wide flat slats and a ladder. The side frames are laminate. The second set of springs and side rails for the other bed is included but is not pictured. Bedding is not included.
Making a convertible twin bed ottoman is not as difficult as it sounds, especially if you purchase the basic components ready for use. For this project you will need to find a twin bed sized fold-away bed and mattress and a hollow frame ottoman that is large enough to hold the twin bed frame.