There is a simple and effective system for this level.
Have them write all their cron stuff in their crontab-let pad
Set crontab-alarm clock to go off at appropriate times
Type in commands from crontab-let pad.
Never fails
--
A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet, balance
accounts, build a wall, set a bone, comfort the dying, take orders,
give orders, cooperate, act alone, solve equations, analyze a new
problem, pitch manure, program a computer, cook a tasty meal, fight
efficiently, die gallantly. Specialization is for insects.
-- Robert Heinlein