Hi,
I think you first need a Moodle site that can be reached by your students. Do you have that site? Remember Moodle is a program that works with a web server.
The web server might be one hosted on the Internet, or one hosted on an intranet (school or classroom network), or one that is on a single computer (stand alone computer in your classroom or perhaps on a laptop) without any network connection.
Adding/editing a lesson has help about creating a lesson.
Finding and Selecting A Web Host as some information about web hosts.
Hope this helps, - Chris