.container {
width: 1000px;
height: 500px;
background-color: cyan;
border: 1px solid red;
}
.box1{
width: 100px;
height: 100px;
background-color: green;
margin-top: 200px;
margin-left: 200px;
}
<div class="container">
<div class="box1">
</div>
<div class="box2">
</div>
</div>