app.component.html

<cse-header></cse-header>
<cse-navigation></cse-navigation>
<main>
	<mat-sidenav-container class="example-container" hasBackdrop="false">
		<mat-sidenav #rightAddCourse2 mode="over" position="end">Drawer content 2
		</mat-sidenav>
		<mat-sidenav-content>
			<mat-sidenav-container>
				<mat-sidenav #rightAddCourse class="add-sidenav1"mode="over" position="end">
					<div>content
						<button mat-button class="btn-primary" (click)="rightAddCourse2.toggle()">Next side nav</button>
					</div>
				</mat-sidenav>
				<mat-sidenav-content>
					<router-outlet></router-outlet>
				</mat-sidenav-content>
			</mat-sidenav-container>
		</mat-sidenav-content>
	</mat-sidenav-container>
</main>