start a discussion

What do you mean when you say "Home Screen"?
Are you asking about a web site, this we site. an application on a device with a screen, or something else?
What do you mean by "a chat"?

Here in the Community, where this is more than just Discussions, we have to pick the appropriate category in which to Start a discussion. A workflow in which a Start a discussion button appears on the home page, then prompts for the section might be useful, but this should be low on the list of thing which should (but apparently never will) be fixed or improved on this site.