What is a Kingdom Hall for Jehovah's Witnesses like?

I'm thinking about writing a screenplay centred around two Jehovah's Witnesses, however I have little to no knowledge of the faith. I'd like to know, what would a kingdom hall lecture contain? Is it similar, in structure to that of a Christian church? Also, I'd be interested to know what Jehovah's Witnesses do/say when they knock on your door in an attempt to convert you. How do they spread their teachings? Are they subtle, are they aggressive, do they quote the Bible when doing so etc. Any other knowledge or insight on the religion would also be much appreciated. Any and all help is much appreciated, many thanks!