How do I add a tab to my home page I have created a page for our website, but I do not know how to add it as a tab on the home page. How do I do that?
The front-end of a Craft site is 100% custom and leaves you with complete control over the HTML, CSS, JS and images that are generated, so there's really no way for us to give you step-by-step instructions on how to make specific changes to the front of your site

Generally speaking, you can modify the HTML and content of your site from the craft/templates folder on your server.  Any CSS/JavaScript/images on your site will likely live in your public HTML folder on your server.