Sketch the journey on paper

Draw the phone. Three boxes is plenty: arrive → act → done.

Example — Sunday rota:

1. Arrive: this week’s names.
2. Act: tap “I’m covering Saturday” (or just a note that says who to call — a form can wait).
3. Done: the list looks different, or the person knows who to ring.

If step 2 needs a database you do not have, make step 2 “read the number and call”. Honest software beats a broken form.

Copy

Write the words on paper first. Use the language the user already uses. “Stock” or “crates” or “shift” — not “inventory module”.