for( let i = 0; i < 100; i++) {
const btn = document.createElement("button");
btn.innerText = "Hola!";  document.getElementById("container").appendChild(btn);   
}

Make a button and repeat it 100 times. What’s the point of this? That was the exercise and I wrote the code. Learning to manipulate the DOM sounds cool, but the exercises don’t make you see how it’ll be relevant. Hopefully, soon enough though.