Carlos: “I need help with the platform.”
Carlos said that he needed help with the platform. (Say + general information)
The teacher: “Complete the assignment before Friday.”
The teacher told us to complete the assignment before Friday. (Tell + imperative → use infinitive without “to”)
Laura: “Can you explain the grammar again?”
Laura asked if I could explain the grammar again. (Ask + yes/no question → if + subject + verb)