Hello from San Francisco. I'm trying to use Magento for a hobby site, who knows, maybe I'll end up selling something in the future! But right now I'm just trying to solve why I get a 404 error when trying to access the admin panel! Didn't happen yesterday, but it's happening now. I'll find the right spot to post this and hopefully someone can help!
Welcome to the community forums!
The best way to start here is to ask and try to help into the forums. So you're in the right path!
Remember you'll find information on StackExchange too and you can start diving into the http://devdocs.magento.com/ not only for learning but to correct and improve the docs.
Another recomendation could be to be aware of Magento issues on Github: https://github.com/magento/magento2/issues (if you are technical, of course).
Also, you should read this post: https://community.magento.com/t5/Welcome-to-the-Magento-Community/Start-here-and-hello-from-me/m-p/5... (in particular the guidelines)
Regarding with your issue, can you share which version of Magento are you using?