Northgard

The 3 secret objectives are:
500 food,
Explore all abandon houses,
Build the longboat dock by year 3

Make sure to build your woodcutters lodge on the forest tile directly above the starting tile and also have both the farm land and hunting grounds up and running a.s.a.p they are both adjacent to the starting tile. Keep your population cap up so you can get as many idle villagers as possible idle villagers means more food. Dont build the longboat dock until you have done the other 2 secret objectives as building it will complete the chapter.

Its a pretty easy achievement to unlock the game will basically walk you though it and if you dont get it on the first try your completed objectives carry over so you can go back and only do the ones you need.