One of the main reasons for giving out this free content is to get prospect to give you their email address in exchange of an opt-in offer. This could be mini-course, download, cheatsheet or report. At this stage your email marketing provider must provide you automations, meaning emails are sent without your involvement and as per your defined actions.
If you're wondering what a sales funnel is, simply imagine a real-world funnel. At the top of that funnel, some substance is poured in, which filters down towards one finite destination. In sales, something similar occurs. At the top, lots of visitors arrive who may enter your funnel. However, unlike the real-world funnel, not all who enter the sales funnel will reemerge out from the other end.