Try to complete this one… (pay attention onto all the CONSOLE-LOGS) !
$w.onReady(()=> {
$w('#repeater1').data = SOME_DATA_HERE;
$w('#repeater1').onItemReady(($item, itemData, index)=>{
console.log(itemData); console.log(index);
$item('#btnMore').onClick((event)=>{
let selected=event.target.label; console.log(selected);
$item('#box1').show('fade');
$item('#txtBox').text = (Number($item('#textbox1').text)+1).toString();
});
});
});
And do not forget to read the provided link one more time!