When you've downloaded analog, and either you or your browser has unzipped it, you will find in the analog folder a configuration file called analog.cfg and the analog executable itself, as well as the Readme, the Licence (which you must read and agree to before using analog) and a couple of other files.
(Some unzip programs are broken, and do not create folders when they should. If you don't have a folder called lang inside the analog folder, create one and put all the files called *.lng and *.tab into it.)
There are two ways of running analog. You can either run it from Windows (by single-clicking or double-clicking on its icon, depending on your setup), or you can run it from the DOS command prompt (under Start-Programs). If you run it from Windows, it will create a DOS window to run in. When it's finished, it will produce an output file called Report.html. The first time you run it, this may all happen almost instantly. For help in interpreting the output, see What the results mean.
LOGFILE logfilename # to set where your logfile livesThe logfile must be stored locally -- analog won't use FTP or HTTP to fetch it from the internet. There's a sample logfile supplied with the program.
There's a list of basic commands later in the Readme. Also there are a few to get you started in the configuration file already, but there are lots of others available. You can read about all the commands in the section on customising analog.
In some ways, it's easier to run analog from the DOS command prompt, because you get to see any error or warning messages more easily. Also, if you run analog from the command prompt, there is another way to give options, via command line arguments, given on the command line after the program name. These are just shortcuts for configuration file commands.
If you want to compile your own version of analog (it's written in C), or just to read the source code, it's available from the analog home page. (It's the same source code for all versions).