In-app "Visible at launch" checkbox?

I'm trying to figure out how to make a checkbox on a window so the user could select wether or not they want to see the window again. The code would maybe look something like this?

Code:

- ([COLOR="magenta"]BOOL[/COLOR])windowIsVisibleAtLaunch:([COLOR="magenta"]id[/COLOR])sender{
    [[COLOR="teal"]welcomeWindow[/COLOR] ([COLOR="indigo"]method[/COLOR]):[[COLOR="teal"]welcomeCheckBox[/COLOR] [COLOR="indigo"]booleanValue[/COLOR]]];
}

The "(method)" is where the missing method needs to go.
Any help would be much appreciated.

 

"Visible at launch" checkbox

So I did what you said. After 40 lines of code and countless error encounters I have gotten close. Unfortunately, the API guide doesn't give a very good explanation of NSUserDefaults and using them was a disaster. So, I looked at an example for a preferences controller. I used some code to get me by and I think I might be close. Here's the code I have so far:

Code:

#define setBoolDefault(name) \
{if ([[defaultValues() objectForKey:name] isEqual:[dict objectForKey:name]]) [defaults removeObjectForKey:name]; else [defaults setBool:[[dict objectForKey:name] boolValue] forKey:name];}

+ (void)savePreferencesToDefaults:(NSDictionary *)dict {
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
	setBoolDefault(CheckBox);
}

- (void)miscChanged:(id)sender {
    static NSNumber *yes = nil;
    static NSNumber *no = nil;
    int anInt;
    
    if (!yes) {
        yes = [[NSNumber alloc] initWithBool:YES];
        no = [[NSNumber alloc] initWithBool:NO];
    }
	
    [displayedValues setObject:[welcomeCheckBox state] ? yes : no forKey:CheckBox];	
	
	[self commitDisplayedValues];
}

- (void)showIfChecked:(id)sender{
	
	if (welcomeCheckBox boolValue:YES)
[COLOR="red"]Unfortunatley, here I get a syntax error before the "boolValue"...[/COLOR]
		[welcomeWindow makeKeyAndOrderFront:nil];

	
	else {
		[mainAppWindow makeKeyAndOrderFront:nil];
	}
}

I am a beginner coder and it would be helpful to get a detailed answer.
Also, if you know of a way to shorten the code PLEASE TELL because I think I'm going to have carpal tunnel by the time I finish this app!