There are no basic tools to set up a default startpage for particular roles, however, you can set up a startpage for a particular user separately. You can go to the System Users section, choose any user and indicate a Home page in the correspondent field - http://prntscr.com/log70b
within a business process I have a contact object and an account object. I want to associate them and be able to specify whether the contact is the "primary" contact or not.
Do I create a "Connecting contact to account" record? if so, how?
You can read data from Account, then read data from Contact with the following filter - http://prntscr.com/lockqu (or http://prntscr.com/lockvf if you need to find contact which is connected with certain account)