I can't remember the scenario well, it's been a long while, but as tech, the key is to not use swordsmen (preferably at all), but mass create archers. Start the game with JUST workers (and lots, maybe 10-15) and harvest resources while (slowly) starting to build. Get lots of archers (since they are cheap and are ranged) fast. Focus on getting a technodrome when you can spare the resources/workers, and get the aerodrome built (by a technician) and get the two upgrades. You should try and get airships since they are very powerful and effective (but slow). When it's time to attack, take many archers, a handful of airships, and perhaps a couple of guards to absorb hits (aka, a tank).
Things to bear in mind:
-Attack as one large force, not many small ones. You'll work better and be able to guarantee success, as well as suffer less causalities.
-When attacking, select groups of 16 (the current max selectable at one time) and number them (Ctrl + #). Then you can reselect them quickly by pressing that #. Do this for all your attackers.
-Also when attacking, move about 10 spaces at a time (otherwise slow units like airships fall behind and then the attack is weaker).
-Don't send all your units to attack. Keep a small number in the base in case you are attacked.
-If attacked, move any far out workers towards the base so they aren't killed, then focus on letting your men automatically attack the foe. Manually clicking should be reserved for very powerful enemies (such as airships, battlemachines, and dragons), otherwise the constant changing of foes may be too slow. HOWEVER, you can select a group of just archers and have them target a foe, since you need to only click the foe once generally and all the archers will attack it, which will probably kill it for sure, allowing you to quickly defeat foes one by one, which is more efficent than slowly killing them all at the same time. This isn't so good for melee units or slow stuff like airships though.
Try this and if it is still too hard, practice a bit to get to know the techs well and you'll be owning ultra magics and ultra techs in no time!