macOS nsmatrix - calculator

Below is code for a basic ten button nsmatrix(of numbers), which should output the number to a text-field. The difficulty I am having is setting the ibaction (mytextoutput) to the matrix -- I can't do it in the IB. It only allows myMatrix to be set to the matrix, Do I need to do this programatically. I have tried to read about tags but not getting anywhere. The program runs without errors but when pushing buttons nothing happens. Thanks. Adam.

#import <Cocoa/Cocoa.h>


@interface AppController : NSObject {
IBOutlet NSTextField*myTextField;
IBOutlet NSMatrix*myMatrix;
}
-(IBAction)myTextOutputid)sender;

@end

#import "AppController.h"


@implementation AppController

-(IBAction)myTextOutputid)sender
{
[myTextField setStringValue:[[NSMatrix selectedCell]title]];
}

@end