Am I understanding Multisite's functionality correctly (Newbie, trying hard!)

I’m a newbie and I’m trying really hard to understand WP and multisite, however I am not clear on the extent to which the properties of the “Master” WordPress site (my terminology – don’t know the official phrase!) carry over to the network. If you have time to help a newb, I’d be grateful.

Here’s a simplified version of how I imagine it works. Am I right?

– Create one “Master” template site with some pages, some plugins and perhaps some images.
– Press a button and out pops a duplicate of the template site (with the same pages, plugins and images as the template)
– Press a button and out pops another
– On any site in the network I can add a different logo, perhaps add an additional page
– If I make a change on the “Master” site (for example, change the text on one of the pages), that change can be “pushed” to all the sites in the network.

I would be very grateful if you’d let me know whether I’m understanding this right. Any links, suggestions etc appreciated.

Thank you.