To use the useTransition hook to create smooth state transitions, you must first create a transition object. The transition object contains two properties: startTransition and endTransition. The startTransition property is a function that is called to start a transition. The endTransition property is a function that is called to end a transition. To create a smooth state transition, you call the startTransition function before updating the state. You then call the endTransition function after the state has been updated.