where do i define the first route of angular app code example

Example 1: how to add changes every time you route navigate to page in angular

// Place import at the top
import { Router,NavigationStart} from '@angular/router';

//Place the code below inside your class
constructor(private router: Router){}

ngOnInit(){
   this.router.events.subscribe(event =>{
      if (event instanceof NavigationStart){
   		
      }
   })
}

Example 2: this.router.navigate

<a [routerLink]="['/', 'red-pill', {x: 'white-rabbit'}, 'neo']">
  Param!
</a>