Work with legacy and simple sites using jQuery selectors, events, AJAX, effects, and plugins.
Lessons
Walk up the DOM to ancestors and the nearest match.
parent() and closest() is easiest to learn by reading the example, changing it, and observing the result.
const $card = $('.start-btn').closest('.card'); // nearest ancestor
$card.find('h3').addClass('highlight'); // descendant search
$card.children('.body').css('color', 'green'); // direct children
$card.siblings().fadeTo(200, 0.5); // sibling elementsPractice the parent() and closest() example in a small scratch file, then explain what changed and why.