Congratulations, someone downloaded your lead magnet. This introduction is your chance to make sure that they actually read it from cover to cover.
Reading an entire document can seem like a big task. This introduction gives you a chance to convince your reader that they will miss out if they do not take the time to read everything.
Your introduction should be no more than one page long so that a busy person can scan read and still get a good idea of the overall message.
Finish the introduction with a personal message to the reader. Speaking directly to your audience helps to show that the lead magnet was tailored for their individual needs.