The QlikView server and publisher are bundled into one installation package where you enable the publisher functions with adding your publisher license.
The qlikview server (QVS) are used to be reload and present qlikview data in a centralized way by ex. using the accesspoint to list documents for the end user. The publisher part are responsible for more complex tasks such as distributions of qlikview documents (where the QVS can be a recipient).
The QMC are the management interface for where you can organize settings for the QVS and the publisher as well as set up tasks etc.
I strongly recommend that download the server reference manual and you sign up for a training session to get some understanding about the products.