Complete the puzzle on a flat, protected surface
Slide a large piece of cardboard or wax paper under the puzzle
Place a second sheet of cardboard on top
Carefully flip the puzzle over
Remove the backing surface
Apply puzzle glue evenly across the back with a brush or spreader
Let the glue soak in and cover all pieces
Allow the back to dry completely
Flip the puzzle face up if you want to glue the front
Apply a thin, even layer of puzzle glue to the front
Spread the glue from the center outward
Remove excess glue from the edges
Let the puzzle dry completely according to the glue instructions
Mount the puzzle to a board if desired
Frame or store the finished puzzle once fully dry