Do you have a question about the Graco Size 4 Me and is the answer not in the manual?
Adjust headrest to highest position and loosen harness straps by lifting the lever.
Remove strap loops from splitter plate, pull straps through seat, and remove the chest clip.
Unbuckle the harness by pressing the red button and remove the old buckle tongues.
Slide new buckle onto straps, re-attach chest clip, ensuring no twists.
Re-insert straps through seat pad and back, then onto the splitter plate.
Undo clips from seat pad and lift it to pull the buckle through the crotch slot.
Reach under the seat to the metal retainer, push it up, and remove the old buckle.
Insert the new buckle's metal retainer into the crotch slot and pull the buckle through the seat pad.
Wrap seat pad, re-attach clips, pull adjustment strap, and tuck seat pad around recline handle.
Insert new tongues into buckle and perform final checks for security and strap twists.