This suitcase is ready for use right out of the box. Before your first trip, familiarize yourself with the built-in safety lock. The initial combination is typically `000`. To set your personal combination: 1. Ensure the lock is set to `000` and pull up the shackle (or release button, depending on the lock type). 2. While the shackle is up, turn the dials to your desired three-digit code. 3. Push the shackle down firmly until it clicks into place. Your new combination is now set. Remember your combination as there is no master key. For care, wipe the exterior with a damp cloth and mild soap to remove dirt and grime. Avoid abrasive cleaners that could damage the textured finish. Clean the spinner wheels periodically to ensure smooth operation, removing any hair or debris that might get caught. Store the suitcase in a cool, dry place when not in use. Compatibility for airline carry-on depends on the specific airline's regulations; please check the dimensions and weight limits of your chosen airline, as this information for the suitcase is currently unavailable. Info needed: Specific suitcase dimensions and weight.