Some friends who work with kids with autism use noise cancelling headphones a lot.

They also have timelines and schedules. For some kids they literally specify a "T minus" timeline.

Some therapists and parents have found it helpful to have standard routines (procedures) and checklists [1], as a few were Navy flight surgeons and aviators in their other careers. The kids get used to a standardized, but not overly rigid way.

[1] NATOPS (Naval Air Training and Operating Procedures Standardization) https://en.wikipedia.org/wiki/NATOPS