To enable auto boot select the check box 'Boot:' (yellow ellipse):
In auto boot mode the Elf computer will run automatically starting at the specified boot address (orange ellipse). Note that the address should be specified in hexadecimal format.
When auto boot is disabled the processor will not be started, in this case the processor needs to be started manual with the 'Run' or 'G' button (F12 on PC keyboard) depending on Elf type.