This option is available by pressing on the Main Control and selecting Help in the list on the left.
Yes, start EQ for me when I start Pixie.
If this is checked then when you start Pixie it will start EQ if it isn't already running. It will start EQ running from the EverQuest Location you specify. This is optional and is for convenience. You can start and stop EQ on your own at any time; it doesn't matter to Pixie how EQ is started.