Your average home theater setup involving a projector will typically have five primary components: The projector, the screen, the A/V receiver, your sources (i.e. cable box/blu-ray player), and speakers.
Before beginning to build a home theater, it is best to get a budget together, as this will determine how much you will spend, and on what. We won't be going over budgets in this guide, but it will be important in determining what products you purchase.
Before starting, it will be necessary to look at the environment that you will be installing your home theater in. If it is a room with many windows, it will be a good idea to get some good thick curtains to block out light. Unfortunately, no matter how bright your projector is, it will never be able to remove the ambient light that will be reflecting off the screen. The brighter the room, the worse the black levels will be. You will also need to take note of the image size you are trying to produce, and where you would like to mount the projector. Your image size and the distance will determine what projectors you can use. This is called a throw ratio. More information about this can be found here.
Once you have your distance and image size, you can find the throw ratio needed by dividing the distance to the screen by the width of the image. The smaller the throw ratio is, the larger the image will be at a shorter distance. You will use this number to determine what projector will work for you.