HTML :

<div class="grid-layout">
  <div class="header">Header</div>
  <div class="sidebar">Sidebar</div>
  <div class="content">
    Content
    <br>
    Lorem ipsum dolor sit amet, consectetur adipisicing elit.
  </div>
  <div class="footer">Footer</div>
</div>

CSS : 

.grid-layout {
  display: grid;
  grid-gap: 10px;
  grid-template-columns: repeat(3, 1fr);
  grid-template-areas:
    'sidebar header header'
    'sidebar content content'
    'sidebar footer  footer';
  color: white;
}
.grid-layout > div {
  background: #333;
  padding: 10px;
}
.sidebar {
  grid-area: sidebar;
}
.content {
  grid-area: content;
}
.header {
  grid-area: header;
}
.footer {
  grid-area: footer;
}