How to use ICommand for executing multiple methods after Buttonclick

I have a lack of understanding how to use the ICommand inferface for executing multiple methods in a row. Ideally I would like to create a delegate that executes all of the following 4 methods by invoking it (but it doesn't have to be a delegate):

var mongo = DbConn(); //Connection to MongoDB
var artikel = GetArtikel(addReorder reorderView); //returns ObservableCollection<ArtikelModel>
var reorder = GetReorder(artikel, reorderView); //returns ReorderModel
Insert(mongo, artikel, reorder); //inserts new reorder into the MongoDB database (one reorder has multiple articles(artikel))

The View (excerpt):

<Button Name="btnSave" Margin="3,0,3,0" Content="Save Reorder" 
                    BorderThickness="0" BorderBrush="Green" 
                    Height="30" FontWeight="Bold" FontSize="15" 
                    Background="Green" 
                    VerticalAlignment="Top"
                    Command="{Binding SaveNb}">
</Button>

Code Behind:

public addReorderView() 
        {
            this.DataContext = new addReorderViewModel();
        }

The ViewModel (need help here):

public class addReorderViewModel
    {
        //Hook to class DelegateCommand
        private readonly DelegateCommand<Button> _clickCommand;
        private ICommand saveNb { get; set; }


        public addReorderViewModel()
        {

        }
    public ICommand SaveNb
            {
                get
                {
                    return saveNb;
                }
                set
                {
                    saveNb = value;
                }
            }

The ViewModel has a "hook" to the DelegateCommand.cs-Class: DelegateCommand.cs

public class DelegateCommand<T> : System.Windows.Input.ICommand
    {
        private readonly Predicate<T> _canExecute;
        private readonly Action<T> _execute;

        public DelegateCommand(Action<T> execute)
            : this(execute, null)
        {
        }

        public DelegateCommand(Action<T> execute, Predicate<T> canExecute)
        {
            _execute = execute;
            _canExecute = canExecute;
        }

        public bool CanExecute(object parameter)
        {
            if (_canExecute == null)
                return true;

            return _canExecute((parameter == null) ? default(T) : (T)Convert.ChangeType(parameter, typeof(T)));
        }

        public void Execute(object parameter)
        {
            _execute((parameter == null) ? default(T) : (T)Convert.ChangeType(parameter, typeof(T)));
        }

        public event EventHandler CanExecuteChanged;
        public void RaiseCanExecuteChanged()
        {
            if (CanExecuteChanged != null)
                CanExecuteChanged(this, EventArgs.Empty);
        }
    }

Questions: 1. What do I have to do to make the buttonclick execute the above mentioned 4 methods? 2. How do I add other buttonclick events (the view has about 5-10 buttons) into the ViewModel?