If you want to install Discourse the official, supported way, have a look at the install Discourse document on Github. If you install Discourse any other way, you’re likely to have trouble, and if you do, you’ll be less likely to get any help here.
This guide covers the official guide to install Discourse which can be used on your bare metal hosting or the cloud. If you have issues with your installation, feel free to start a topic over at our #installation support category, and someone from the community will help.
Alternatively, if you wish to try out Discourse without installing you can visit Discourse pricing | Discourse - Civilized Discussion and start a free hosted trial.