I guess you're asking how to make a landing page?
There are a lot small things that can be tweaked here. I'll try to point you in a general direction but this really could be a whole blog post for an answer.
Landing page should be attractive and clean. Use an approprate background image or texture. Don't clutter it with a bunch of text. There is no need to have website navigation, one link to the homepage is just fine.
Care that the text and the background are in a good contrast. There should not be a lot of text there so the thing you write should matter. Let the potential prospect know why they should take you up on your offer (you can to that by placing some testimonials or with a short list of the content you are providing or with a short list of what they are geting etc.)
Make sure your Call To Action button stands out. It is always great to have some graphical content that presents your offer like a book cover as one of the more popular examples but this depends on the lead magnet type you are offering.
Also, make sure your landing page is responsive.
A few thing form the top of my head, hope it helps