Follow these instructions in order. Rushing or skipping steps is the #1 cause of instability.
Position the metal spring frame at the desired height. For newborns, use the highest setting to make lifting the baby easier; as they grow and begin to pull themselves up, you must lower the mattress to the lowest setting to prevent climbing out. babi italia parkland convertible crib assembly instructions
(check against manual – typically includes): Follow these instructions in order