My friends and I are trying to make a game in DirectX and I was curious as how to do something. Firstly, I want to take a background image (let's call it "background.bmp"), load it, and then once i load it and draw it to the screen. Once it's drawn, I want to have platforms come scrolling at the player character as i move to the right of the screen. After X number of platforms, I want the scroll to stop and have player character touch a "portal. bmp", which will load the "background2.bmp". I am an uber green n00b with DirectX and I don't even know where I would begin. Any assistance would be greatly appreciated. Thank you for your time.

You lost me at 'platforms come scrolling'
Is the player standing/walking on the ground, where the platforms are hovering above, and has to jump on the platforms in order to reach a portal to the next map?
Or is the game like Bubble Bobble where the map is static and the player moves on platforms?
It the game 2d or 3d? Because in order to do 2D in DirectX you must fake it with 3D unless you use Direct2D. I haven't used Direct2D yet so I don't know.

Where to begin?
•Start by picking a programming language you are comfortable with.
•If you are set on DirectX, possibly start with XNA and learn c#.
•Setup XNA with VS Express
•If you use the DirectX SDK, follow their examples.
•Get used to navigating through MSDN.
•Get some books on math, programming, and game development.

Here is a very basic framework of a game:

Initialize / Load Resources
Main loop:
- Get user input
- Process AI
- Update Objects / Collision Detection
- Draw / Render (Using Direct3D or 2D)
- Play Sound
Reset or Exit

You move Player's character, AI objects, and camera during the Update phase. "After X number of platforms" and touching a portal happens during the Collision Detection phase. Drawing the background happens during the Render stage.

Look into sprites