Start working through the tutorial Nick made here: http://www.chickensmoothie.com/tutorial/tut1/index.html .
To get the file onto the website, go to cPanel (the screen with lots of buttons after you log in on 000webhost), scroll down to "another File Manager". click, double click on "public_html" (all files that you put here can be accessed by people who view your website, so you need it there). If you've worked through the first page of Nick's tutorial, you should have a file called "hello.php". If you haven't, do that now.
So now we're in "public_html" (Note - if this is your first time doing this, there should be a file called "index.html" that acts as a homepage, which you can edit if you like later). Go to the left hand panel, click "upload file", "choose file" then hunt for "hello.php" and confirm, then hit 'ok'. "hello.php" should now be in the folder. Now (preferably in another tab!) go to http://www.coolcools.net84.net/hello.php and you should be able to view that piece of code. You can upload the other files in a similar fashion, and view them by putting the file name after the website name like I did with that link there. :)
That's all you need to know to be able to work through Nick's tutorial. :D Alternatively, if you don't want to do all the coding, you can use www.myadopts.com that sets it all up for you.