I found this to be one of the easier Scenarios. At the beginning, you can select one person to start off at the island to the north east of the map. They will disappear, and reappear there at the beginning of Turn 7.

Once you have made a bit of distance along the bridge towards the fort, ~all~ of the enemy generals will charge you. They're not particularly powerful, so it's not too bad. The Sky Archers are worrying, but they have very little effect on your troops, who should, by now, have decent revisions. If you're worried about the Sky Archers, Tornado or Wind Cutter really cuts them to pieces, and Elves have longer range.

At the start of Turn ?, Craydo and two gladiators arrive at the bottom of the map. By this time, you should have killed everyone else (except maybe the General), so concentrate your attacks to the south. Pikes go through his horsemen easily, whilst other commanders can take care of the Gladiators.