The shape of a control communicates before its label is read. A play triangle promises playback; a slider suggests adjustment; an arrow suggests a destination. Each asks the visitor to act on an expectation the design has created.
Make the next step real.
An arrow on a card suggests a destination. A slider handle suggests movement. If the arrow or slider does nothing, the visitor wastes effort trying an action the design appeared to offer. The mismatch is small but entirely avoidable. The illustration contrasts a play symbol with the fact that no recording exists. The replacement is intentionally modest: a short availability note followed by the written lesson. It shows visitors that they can read the available lesson.
Match each visual cue to a real behavior. Use ordinary text for a status, a link for navigation, and a button for an action. Then make the result clear enough that a person can tell whether the action succeeded. A disabled button can be appropriate when a real action becomes available after a clear prerequisite, such as completing required fields. That is different from a player for a recording that has not been supplied. What visitors see should help them understand what they can do next and what, if anything, they must do first.
Put it into practice.
List the action suggested by each interactive-looking element and verify that it exists. Use links for destinations, buttons for actions, and ordinary text for status. Omit an unavailable media player and keep a useful written path; do not make people discover that a decorative control is inert.
What would someone reasonably expect to happen here?