Creating fonts with BMFont

[TinSleeves]

I'm trying to get fonts working using BMFont and following the Preparing a Font doc, however I'm having a few problems.

What files do you need to come out of BMFont?
When I export I only get a .fnt, I selected PNG in the export options but still only get a .fnt. Any ideas what I'm missing?

[unikronsoftware]

I'm AFK at the moment, but I recall you need to export not save from BMFont. Save just saves the settings.