custom template for a landing page

I’m trying to create a landing page for my site, and I need to give it a new layout, pretty much empty instead of the usual widgets and all. I know that calls for a custom template–

And I can’t find anything that tells me what the minimum code for a custom template IS, or the simplest steps to set it up. I know everything is on the forum somewhere, but I want a simple code for a blank page and the setup steps to put it in.