How can I disable multiple buttons?

Question

hi, So I have in a NavigationBar a "+" button and 5 disable buttons in my view.

When I push the "+" button I want to enable the first button and when I push again that enable the second...

I have tried with that code

if (Button1.enabled == YES) {
    Button2.enabled = YES;
}

I really don't understand how I can do that... Thnaks for your help