The first stage is locating Lev, the partner of Caele, and healing him. After you heal him, Lev will send you down the path to find Joshua. There are monsters along the path, but they should not be any trouble. After you speak to Joshua you will need to build a base and create a small army. The game will require at least fifteen units, which--once added to your heroes and the three clerics you later receive--should prove more than enough to take down both of the Orc bases to the east. The rune that Rohen sought is on the orc leader named Krong. After you retrieve it you will speak to Joshua twice more. You will then head to the portal where a group of enemies will appear to block your path. Rohen will appear and use powerful Ice magic to destroy them. He will then retrieve the rune from Tahira and teleport away, Joshua will also leave via portal.
If the player so desires they may then head south to learn more game information from a series of statues, or simply head west into the portal and begin the main campaign.