MAMP talking to wordpress account

Hello,

I am a newbie in wordpress and trying to figure everything out as I go along. I have been watching some tutorials on lynda.com trying to make everything work the way I want.

It has been going smoothly so far but I have a question which is probably straight forward but for me it’s not. So here it goes:

I have installed wordpress and MAMP on my Mac and I have followed the steps to make them talk to each other. Now my question is: how do I make MAMP talk to my actual wordpress website (the-apposite.com) and not one that is created during installation of MAMP?

Am I missing something here?

What I want to do is basically be able to customise my theme (ie. change things from the top, search bars, next and previous buttons etc.) I want to create a blog that looks exactly as I want it to look and a theme is not out there to provide me this.

Thanks in advance
All help appreciated