So all waht you need to do is go to game's files and change it's level's data

So, go to local files of your game (Right click on Wooden Battles => Properties => Browse local files)
Now you should have thisGo to "Wooden Battles_Data"
Then go to "Missions"

Now find Missions that have 3 numbers (for example "Mission100)
Open it
Right now we have this
Just delete everything from Blue team (DONT DELETE "Blue Team" ITSELF, DELETE ONLY THAT UNDER THAT LINE)
And boom! now your level would be clear and you simply place 1 unit and wait until it reaches enemy's base

For other challenges make the same, numbers means what challenge it is, for example if it is "Mission100" then it is the first challenge of rifflemen. If it is "Mission602" then it is second challenge of commander.

Thx for reading this very fast made guide, i hope it helps you, cya!