Trouble with buttons and using variables

Hello all, I have used flash a lot for basic animation but struggle with actionscript. In an effort to learn this side more I have done many tutorials for basic actionscripts. Now I am trying to do a bit more with buttons and using variables but cannot seem to get this right. If theres anybody here thats good at this sort of problem that could explain to me where I am going wrong I have attached a file showing what i am thinking and hopefully what i am trying to do?

I have 3 buttons on the main timeline that control 3 movieclips which tween a small ball to bigger then stop.

Then, when any of the buttons are pressed they should make the current big ball tween to small again then once that’s complete, tween its own movieclip ball bigger then stop.

I’ve also tried to make an argument so if you press the current button twice nothing happens as its already correct.

Am I doing this the right way but the code is wrong? or should this be done another way. Thank you.