The game really isn't that difficult, just clear the maps one after another, recruiting stronger allies and buying better weapons as you go. Contrary to what the tutorial says, you shouldn't avoid fights, since defeating enemies is the best way to make money and level up. In the early stages you might want to craft bombs or javelins to deal with the enemies until you gained some levels.
Thanks a lot, but don't get your hopes up too far. I haven't found the time to proofread and fix the current version of the translation yet, so it's probably riddled with mistakes. The game itself is also kind of disappointing compared to thanatos. From the game files it seems like the dev originally wanted to make a tower defense game with a much more complex story, but eventually abandoned that idea and we got a very basic rpg instead.