Take stock of your pieces. There are four major components of a cello: the front, the back, the ribs, and the neck.
Remove any old, dried glue from the cello ribs using a utility knife. Use small, short strokes to avoid damaging the finish or the wood itself.
Apply a half-inch strip of hide glue along the entire circumference of the front and back of the cello ribs.
Place the ribs on top of the maple back piece. Make sure the instrument is lying flat on an appropriately sized work bench.
Quickly and carefully place the spruce front on top of the cello ribs, sandwiching the ribs between the front and back of the cello.
Clamp the front and back to the ribs and allow to sit overnight (at least 12 hours).
Remove the clamps and stand the cello up.
Apply hide glue to the neck bevel and press the cello neck in place. Allow up to 12 hours to dry.
Snap the bridge to the body and string the cello accordingly.