new fitbit user, have some questions about logging.

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I've just gotten a Fitbit! I just synced it up with MFP but am unsure how to log my exercises now. I wear the fitbit all the time while exercising (except for swimming). I usually log in each exercise into MFP, but now that the fitbit counts the steps which I assume is also the movement and not just forward motion, I'm unsure if I am supposed to still log in my exercise such as walking, running, dancing, weight lifting, etc?

also for swimming I saw that there is a way to log that in on the fitbit site, but if I log it in here I shouldn't have to do it there, right?

Can someone shed some light on how to use these two tools (Fitbit and MFP) together? Or show me where on either site it explains it all? I'm feeling lost! Thanks!