To assemble a Graco Pack 'N Play Playpen, lock all four rails before pushing down the center of the playpen. If the center of the floor is pushed down before the rails are locked, the sides of the playpen do not raise properly.
Each of the top rails of the Graco Pack 'N Play must be locked in place before a child can use the playpen. Pull up on the bottoms of two opposing rails until they lock into place, and then repeat with the other two rails. All the rails should produce an audible click when they lock. Push down on the locked rail to ensure that it is rigid before proceeding with assembly. If the rails are not rigid or lock with an audible click, consult the Graco Pack 'N Play manual for further instructions.
It is important to lock the rails before lowering the playpen floor. Lowering the floor before locking the rails interferes with the locking mechanism and makes setup difficult. Similarly, when disassembling the Pack 'N Play, raise the playpen floor at least halfway before unlocking rails. Some new playpens may need to be stretched before the center stays down. Graco recommends placing several books or a similarly weighted object on the center of these playpens before the first use.