<div class="container">
    <div class="item"></div>
    <div class="item"></div>
    <div class="item"></div>
    <div class="item"></div>
</div>

.container {
    width: 600px;
    height: 200px;
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-template-rows: repeat(2, 1fr);
    grid-gap: 15px;
}
.item {
    border: 1px solid #000;
    background: #ccc;
}
.item:nth-child(1) {
    grid-column: span 2;
    grid-row: span 2;
}
.item:nth-child(2) {
    grid-column: span 2;
}