Dreaming of a broadcast means seeking attention and getting the word out. Try dressing up better and improving body posture to stand out among the crowd. It will naturally appear attractive to strangers and peers. Speak louder and with conviction. Practice on forming strong opinions.
Once the attention is all on you, stick with the messaging. Repeat as many times as necessary about the same thing until people really understand the your message. If they empathize with the message, then you have succeeded with the broadcast dream.