Help installing some Java and Flash

I have Git now and some other stuff, but I've looked around and all and I don't get very helpful information. I've used these instructions:

1. Download the latest version of Flash Player from the Adobe Website.
   Click on Download the Latest Player and choose ".deb for Ubuntu" from the dropdown list.

2. Choose "Save File" from the pop up window.

3. Open a terminal window.
   The terminal window will be found under Applications -> Utilities.

4. Change to the directory where your downloaded file was saved.
   cd Downloads

5. Install the libcurl3 library. sudo apt-get install libcurl3

6. Install the Flash Player.
   sudo dpkg --install install_flash_player_<version>_linux.deb
   Replace with the latest version number.

7. Restart Firefox.

8. Check that Flash Player was installed.
   Type about:plugins in a browser window, and look for the Flash Player MIME type.

Read more: http://www.ehow.com/how_5068467_install-flash-player-ubuntu.html#ixzz2ixPj47qS

What I don't understand is how I change the directory and all that crap which they say everyone knows.

1 - Open Terminal

2 - Copy & Paste Command:

sudo apt-get install ubuntu-restricted-extras

3 - Press Enter

4 - Type in your username

5 - Press Enter

You have not just installed the Ubuntu Restricted Extras, one part of that is Flash.

Ubuntu Restricted Extras

To install Java, please follow the instructions:

Easy Linux Tips: Installing Java