An incident light meter can be of benefit in certain contrasty lighting conditions, especially for transparency film.
I suggest that you put the meter away for a while until you've had a bit more experience using your cameras (and possibly some different films). Then, if you start exploring difficult lighting conditions, you should do some reading on exposure measurement and how to make the most of film latitude, etc. This is where a meter comes in useful.
Bookmark the following for later (it may not help you to tackle it straight away): Kodak website - this has a great section on exposure meters. Cambridge-in-colour website is better illustrated, but less comprehensive. (NB the rest of the Cambridge site is quite helpful, too).
.T.
The internet, and Google in particular, is your friend.