JSFiddle - React, Tailwind, and code Playground

HTML

<div class="tets">
<div class="popup"></div>
<div class="popup"></div>
<div class="popup"></div>
<div class="popup"></div>
<div class="popup"></div>
</div>

CSS

.popup {
    display: none;
    width: 150px;
    height: 150px;
    margin: 10px;
    background: #060;
    float: left;
}

JavaScript

$(".tets .popup").each(function(i, el) {
    $(el).delay(3000 * i).fadeIn(1000);
});