Ion-select: How can I make a text dependent on a variable?

Hello, I have already created the following code. Now I would like to display a different text block under the selection field for each individual value. How does this work?

    <ion-select value="B" [(ngModel)]="selected_organisation">
      <ion-select-option value="B">First</ion-select-option>
      <ion-select-option value="U">Secound</ion-select-option>
      <ion-select-option value="W">Third</ion-select-option>

Do you know angular? And *ngIf ?