When you first configured your Discourse forum, you were greeted by the Setup Wizard. It’s a really useful tool that’s been developed to make it even easier to get a forum up and running.
As an admin, you can re-run the Setup Wizard at any time (and as many times as you like) by logging into your site and appending /wizard to the URL in your browser’s address bar.
For example: If your site is at https://forum.example.com, to re-run the Wizard login to your site and then go to https://forum.example.com/wizard.
Re-running the Setup Wizard is a great way to update your site’s basic setup all in one place. You can even skip straight to specific pages using the shortcuts included in each section of this overview.
It can happen that, as apparently occurred to @natefinch at other post, sometimes you can’t make work categories as your default home page. It happened to me, as well! Then, or you use the solution offered at this same thread, or you… erase the cache and cookies!!
For the people who doesn’t know what this means I was going to explain to you why this matters at all, but I prefer to let other people do it. Why to do the same thing twice or more times when is already done? This guy, Leo, can explaining to you just fine.