You need to take care of the following:

1. event handlers need to be mapped to a function:

   <button onClick={this.onChallengeButtonClicked}>Start<button>

2. You need to tell each button to which item it corresponds to:

   <button item={item} onClick={this.onChallengeButtonClicked}>Start<button>

3. Event handler function can detect which button item was clicked by accessing the event parameter: onChallengeButtonClicked: function(event) { item = event.currentTarget.item; window.location.href = item.title; }

You need to take care of the following:

1. event handlers need to be mapped to a function:

<button onClick={this.onChallengeButtonClicked}>Start</button> 

2. You need to tell each button to which item it corresponds to:

<button item={item} onClick={this.onChallengeButtonClicked}>Start</button> 

3. Event handler function can detect which button item was clicked by accessing the event parameter:

onChallengeButtonClicked: function(event) { item = event.currentTarget.item; window.location.href = item.title; }