Angular PrimeNG multiselect: how to programmatically select only part of the options from a list?

Question

Angular

I have a PrimeNG multiselect, I get the options data for it from the server during initialization, the problem is that all list items are automatically selected, and I only need to select some items with certain IDs. I found a post on the Internet that you can add list items that should be selected using [(ngModel)] pushing them to the appropriate array, but my implementation does not work:

<p-multiSelect [options]="locations" [(ngModel)]="selectedItems"                                 
                                 [formControlName]="'locations'"
                                 [maxSelectedLabels]="1"                                 
                                 defaultLabel="Select office"
                                 optionLabel="address"
                                 dataKey="id"
                                 [filter]="true"></p-multiSelect>

All items in the list are selected anyway. The doc has a couple more words about the SelectItem API with similar examples, but I don’t understand how to make it work. Who knows tell me please!