REACT: How to load data correctly

I need to load session data when user click on session name. I have multiple “session” elements so I need to use array or smth. Which type I should use in state and how to push in it?

<div className="session" onClick={()=>{
// How do I push into state
}}>
<p>Session name</p>
// How do I check if data is loaded
{loaded && <div className="session__data">
// How do I put loaded data here ?
</div>}
</div>