Re: Why can't I use this?
Did you try that? The compiler will alert you any problems. If you can't understand what the compiler is grumbling about, post the entire message that it gives.
You should not be putting so much into the static main() method. Apart from anything else the static context won't make easy (as you've found!). The frame and button should not be static, and main() should create an instance of SecondClass to access them and their actionPaerformed() method.
It would also be a good thing to follow the overall structure of Swing programs used, eg, in Oracle's Tutorial. I would highly reccommend that you read the examples and commentary the Tutorial contains.