Should I learn Zope and/or CMF before I start with Plone?
There is so much software here! Is it easier if I try to learn myself Zope of CMF before using the full Plone stack?
In general, it's easier to start with Plone. Lots of effort has been made to smooth out the steep learning curve of Zope and the CMF, so Plone should be considerably easier to work with if you're new to the whole technology stack.
Starting with Plone, you can get the basics up and running, and be productive — then you can start digging downwards from there, and learn stuff like Python, ZPT and how Zope works as you go along.
You don't need to understand the whole software package to be productive and effective with it — that's part of why Plone exists, to make the process less complex, and to make it easier to do the common tasks.