Google analytics - Set up data points and funnels

Hi
I would like to record data points (events/tags) on my google analytics account so that I can tell which visitor visited which key page and whether they converted or not.
I.e I would like to know how many visitors converted that also visited a specific blog page, the blog page would be a key page that would have an event/tag attached to it.

I would also like to know total visits for each key page.

I would also like to know which source has which amount of conversion, currently all my conversions are recorded under website even though they may have come from facebook, twitter ect

I would like the the data points to be added and to be taight how to add future ones my self.

Please advise?

Thanks