Setting up A2CLOUD requires installing a bunch of stuff on your Pi. I’ve tried to make this easy.
If you have never used your Pi, you will need to load your SD card with either Raspbian or A2SERVER (which is based on Raspbian). If you don’t plan on using A2SERVER, and have a screen and keyboard attached to your Pi, you can use the fairly easy NOOBS installation process described on the Raspbian download page.
If you are instead installing the Raspbian or A2SERVER image file, you might find my Raspberry Pi Party page useful, particularly if you have a Mac. From there, you can get Pi Filler, which is a self-explanatory tool for loading up your SD card. For non-Mac platforms, you can look for guidance on the Raspberry Pi wiki and forum to accomplish the same thing.
Once you’ve loaded Raspbian, the next thing you need to do is put the SD card in your Pi, and attach power. If you’ve got a screen and keyboard attached, you’ll see it boot up. If not, you can log in with SSH from another computer. If you have a Mac, you can use Pi Finder to help log in to your Pi from Terminal. If you have Windows, you can use Advanced IP Scanner to find your Pi on your network, and PuTTY to log in. The username is “pi”, and the password is either “raspberry” or “apple2”, depending on whether you have vanilla Raspbian or A2SERVER installed.
Once you’ve logged in and found yourself at the Linux prompt, type
sudo raspi-config and choose the first option in the menu to expand the filesystem. Then reboot when it asks you to.