I'll take a stab at this since this is what I have been working on.
It is real easy, go to Tools then select preferences, when the preferences menu shows up scroll to the right to the still capture tab, these are your settings for autostill capture. You will see a setting for the amount of time.
While you are in preferences go to the general video tab, here you can select the folder that you want your stills stored to.
To start the Autostill capture you can select tools again, at the bottom of the dropdown menu there is an item Video Functions there you can start or stop Autostill or you can have it start when to application starts, this selection is in the preferences menu.
