Arduino ligths on/off clapping hands
If you start from the beginning of the project, instead of trying to jump in half way through, you'll know precisely what components you need.

Your first step shouldn't be trying to order components, but to identify (through research) how the technology works.

Second is to find out how it can be implemented, by looking at existing schematics and designs that other people have created.

Third is to design your own schematic.

Fourth is to prototype it.  It's only at this stage that you should be thinking about what components to order.

Go back to stage one and do the research. Thanks to the likes of Google it'll probably only take you a few minutes.