You can determine the files needed for your install by reading the rest of this page for guidance.
There are versions for both i386 (32-bit) and amd64 (64-bit) architectures, this architecture is noted in each of the filenames for download. The amd64 architecture (which works even on Intel 64-bit CPUs) can address more memory and may have other performance advantages, but requires a compatible CPU. If you have a 64-bit capable CPU, use the amd64 version.
The USB memstick image is meant to be written to disc before use and includes an installer that installs pfSense software to the hard drive on your system. This is the preferred means of running pfSense software. The entire hard drive will be overwritten, dual booting with another OS is not supported.
The USB memstick file is named pfSense-CE-memstick-2.4.0-RELEASE-arch.img.gz. where arch is i386 or amd64, depending on the CPU architecture of your system.
|pfSense-CE-memstick-serial-2.4.0-RELEASE-arch.img.gz||USB memstick installer (Serial Console)|
|pfSense-CE-memstick-2.4.0-RELEASE-arch.img.gz||USB memstick installer (VGA Console)|
|pfSense-CE-memstick-ADI-2.4.0-RELEASE-arch.img.gz||Netgate ADI installer|
|pfSense-CE-2.4.0-RELEASE-arch.iso.gz||CD Image (ISO) installer|
|*.md5||MD5 hash files for download verification|
|*.sha256||SHA256 hash files for download verification|