Welcome to the Sylvan campaign. This faction is all about teamwork, focusing on speed, luck and morale. Since positioning and unit cooperation is a big deal in this faction, it seems to me that the Quick Combat option makes you lose a lot more units that playing manually.
Let me give you a quick run-down on the creatures: pixies are fragile, but quick and will get no retaliation once upgraded. They're actually great units since you get so many of them cheaply. Dryads are interesting, as they're not very powerful, but work as a support unit, giving defensive and healing bonuses. Position these right and you have a very good team player. Hunters are very powerful shooters since they get double attacks once they're upgraded, and since they don't cost too much either, they're probably the best ranged core creature in the game. On to the elite: druids are very good, but their cost and growth rate make them less important in the army than the hunters are; blade dancers are very quick damage dealers who can hit all neighbouring units. They aren't very resilient, but the can't be flanked. The moon doe aren't too special, but once you upgrade them to sun deer, they have an incredible +20 morale and luck boost on the neighbouring creatures. Having played the faction for a while, one thing you notice is that this creature keeps getting extra turns. The faction does have a dragon in their army, and its particular ability is regeneration. These things just never die, unless you kill them fast. The treants have ranged attacks and are very strong units that can also provide cover for allies. One good setup is having a sun deer and dryads stand next to the hunters and treants, so they get boosted by their presence.
So, map 1. You start off in serene, exotic surroundings, with your starting hero Wysloth. Wysloth's main skills are Defence, Leadership and Nature's revenge, and those are all good to level him up in; the first two are general skills that work well with any living armies. Nature's revenge is about «marking» enemies and gaining bonuses when attacking those, and it may seem like a silly skill (and the novice level skills are), but if you get it to the top level, we're talking critical hits on every hit for those marked creatures. He also has access to air and earth magic, I suggest getting him air magic since it's a buff for the hunters he will eventually have in his armies. He needs mana, so make sure you get some skills increasing that. You should also get some Offence.
At the start, you're on foot. Not much to see or do but move north to get yourself a ride in the form of a unicorn. Head west to find some starting battles and free creatures to get some experience. There are also a couple of nice items around, so fight your way to them. As you follow the moving stags, you come across some big stones and more free creatures. Keep moving west until you find Danan. She's lonely, so go talk to her. (Note that Dragon Nexus, it's needed later when you run out of mana). She wants you to follow her home. Do. When you reach her town to the north, you will get some development in the story and also gain access to a town, and Danan will join you.
Start building your town. Get a magic guild up so you can get some spells eventually. Make sure you get hunters asap. Keep exploring the island, picking up resources and fighting creatures. There are mines all around. Get them all; you need resources. What for? Well, there's a quest: build a special ship. No rush, though – keep exploring and gaining levels.
Look around the map, take the easiest fights first and keep going back to town for reinforcements and go back out for the harder ones. There is no hurry, so use this opportunity to learn about your creatures' abilities and what kind of spells go well with your army. Obviously, «stoneskin» and «storm arrows» are good in general.
When you have cleared out the island and grabbed enough creatures, head to the shipyard east of your town and head out on the ocean blue.
Due east is the maelstrom (your quest target), but you can explore some first. There are small treasures around, and if you try to go northwest, you will see the cyclops that the elves talked about, blocking your escape so you can't go that way. Go back. When you're ready, head through the Whirlpool and go to the eastern shore. Head up the path and attack. It's a fairly easy fight, just 5 cyclopes and a local guard.
After you have taken the fort, head back to the ship and sail it out to sea. The map ends when you head through the Whirlpool out there.