In order to run IRI and sync with the network, you need to have neighbors which want to pair with you. The easiest and fastest way to get neighbors is through our Slack, where you can join the
#nodesharing channel to find neighbors.
It should be noted that you have to share your own IP and port with your neighbors as well, because IOTA relies on mutual tethering for the data exchange. If you need help simply ask on Slack.