Madrid Airport Transfers

I will be arriving at Madrid airport terminal 1 and transferring to terminal 4s flying on to Morocco, and I'm seeing some conflicting information regarding how I navigate the transfer between terminals. Do I need to take the shuttle bus to terminal 4 then the automatic people mover from 4 to 4S, or can I take the automatic people mover directly from terminal 1 to terminal 4S. I expect to have my boarding pass and all luggage in hand.