how to insert multiple data into the database using angular

Question

https://www.c-sharpcorner.com/article/angular-7-multiple-data-save-using-formgroup-formarray/

in this link explain about how to insert data using form array but not to the database.

 

SaveData()

{

console.log(this.SchoolDetailsForm.value);

//pass this data to service and api node/webapi

}

 

it will print all the data of class details with in the form.i want to display single class detail.how can i do?