Small helping hand. Search for the Dumb-me guides, Without Tears series of documents. There was not one yet written for AsteriskNow but the one for PIAF or trixbox will do as both use the same GUI and make it all 90% the same.
While jumping in and winging it is a great thing it also helps to do some reading to get a understanding of everything so that you don’t go through exactly what you just did.
Yes distro’s make it look so easy. You download a ISO, burn a disc and pop it in and 25 minutes later yes you can have a working phone system. BUT 95% of the time the first time that does not happen as you don’t know how it’s all laid out or what things mean terminology wise. So doing some reading to get up to speed is the best thing.