The concept is that wind is managed by two things you control: the loop you send into it, and which side of your body the line travels on.

Into a head wind or a tail wind, focus on the loop being thrown into the wind. Its fly leg must be straight and line speed increased, with the trajectory matched to the delivery — up in back and down in front into a head wind; a flat or slightly lowered back cast followed by an upward forward delivery in a tail wind. Wind punishes a curved fly leg, which is why the guide says very straight fly legs are necessary when casting in wind.

With the wind on the casting arm, safety governs everything. For a light wind, keep the line on the upwind side of the caster for all or part of the cast; for stronger winds, keep it on the downwind side throughout the cast. That is why the task asks for three methods.

Teach one wind direction at a time, and explain the problem and its safety concerns before you demonstrate.

Source

From the CI Study Guide (2025) (PDF) — Task 22 and the rod-deceleration section on straight fly legs; terms from the FFI Fly Casting Definitions.