Two ways - modal and non-modal.
non-modal - select the PROGRAM MONITOR display. It looks identical to the program editor display. In auto mode, there should be restart softkeys - cursor down to where you want to restart and hit go.
Modal - In auto, on the position page, there is a restart softket to the right. It gives you a dialog window -
 Work No. - just hit input unless dealing with a sub
 Sequence No. - N word you want to point to
 Block No - lines from the N word you want to restart at
repeat number - how deep you are nested in a sub program - usually 0
QUIRK - will MODALLY RESTART everything fro mwher eyou dial it in, EXCEPT for SPINDLE START.
Technique - MDI mode - S2000M3 to start the spindle by program, then go to memory and do the modal restart.
practive this repeatedly - the TWO RESTARTS on a mazatrol fusion are both BEAUTIFUL! - the thing not as beautiful is the unfortunate choice of words "block" and "sequence" - which do not mean the same as what an American CNC programmer takes them to mean!
another quirk - if you moved the slides, they move from point in space to program position by manual feed rate over ride setting until its where the program wants it to be, then program FR will take over once it's read again - which is why practice is good.