Fold a bi-fold futon mattress in half to create the seat portion and back portion of the couch. The length of the bi-fold mattress makes up the seat portion of the futon couch.
Fold a tri-fold futon mattress in thirds to create the seat portion, the back portion and an extra portion. You can either drape the extra portion of the tri-fold mattress over the back of the couch frame or you can fold it under the seat portion of the couch to make a larger seat portion. The width of the tri-fold mattress makes up the seat portion of the futon couch.
Unfold the bi-fold or tri-fold futon to make the futon couch into a bed. Move the couch support from a sitting position to a flat position to support the mattress. Place the flat mattress down onto the mattress support.