Is there a How-To get MRTG works with 3324?

Once you have mrtg installed and running, the configuration is done by running the cfgmaker perl script. (see below)

mrtg should identify automatically the SNMP information (MIB) inside the switch (Dell 3324) and generate the running configuration for the device.

Even though the "official" list of devices supported is listed at http://people.ee.ethz.ch/~oetiker/webtools/mrtg/compat.html , it clearly states that mrtg should work with any SNMP compliant device.

One thing you also need is to configure the management IP of your switch.  You should be able to display the Web management page in order for mrtg to work with your 3324.

If you can see the 3324 web page, and have a default installation, just follow the instructions at http://people.ee.ethz.ch/~oetiker/webtools/mrtg/mrtg-unix-guide.html it's basically the same for Linux (Fedora)

This is the example shown at the above link.

The next step is to configure mrtg for monitoring a network device. This is done by creating an mrtg.cfg file which defines what you want to monitor. Luckily, you don't have to dive straight in and start writing your own configuration file all by yourself. Together with mrtg you also got a copy of cfgmaker. This is a script you can point at a router of your choice; it will create a mrtg configuration file for you. You can find the script in the bin subdirectory.

 cfgmaker --global 'WorkDir: /home/httpd/mrtg'  \
          --global 'Options[_]: bits,growright' \
          --output /home/mrtg/cfg/mrtg.cfg    \
           community@router.abc.xyz

This example above will create an mrtg config file in /home/mrtg/cfg assuming this is a directory visible on your webserver. You can read all about cfgmaker in the cfgmaker manpage. One area you might want to look at is the possibility of using --ifref=ip to prevent interface renumbering troubles from catching you.