What will you require to run DansGuardian? See below.
You must already be running a fairly recent distribution of Linux, FreeBSD, OpenBSD, OS-X or Solaris. You also need to have squid running and configured on port 3128.
Note that DansGuardian should be able to be compiled to run on any distribution of an *nix operating system.
DansGuardian is a filtering pass-through that sits between the client browser and the Squid proxy. It listens on port 8080 and connects to squid on port 3128. So you must have no other daemon running already using port 8080.
You will not need a web server for the default configuration since DansGuardian will automatically display the full error page that does not contain any graphics.
If you are going to build DansGuardian from source, you will need the standard development tools installed such as glibc, autoconf, gcc and make (PCRE is also recommended). Debian users will also require zlib1g-dev. The default Redhat installation and most others come with these installed so you don't need to worry about them.
Most of the time during installation you will need to be logged on as root. A more experienced user will be able to determine when, however for most people - stay logged on as root for the entirety.
Make sure you have all of the above installed and working before you continue.