As a beginner, you are not doing so bad. However, when i wanted to play this scenario, i had to go to the editor and change to an option so i could play as player one and not as player 4. about the map design, i guess it was okay. you painted the terrain with more than one color. different kinds of forest were used in this scenario. the little village of player 2 wasn't that bad. the houses were facing different direction and that make the little village look nice.
I think there was no problem with the triggers. however, if you wanted to put objectives, you just had to make a trigger with the effect OBJECTIVE and the condition ALWAYS (or could be another condition) and runinmmediately if you want the objectives icon to appear as the game starts.
It should have been better if you put player 2 as NEUTRAL instead of ALLY. you should make a trigger that when player one is at LOS, then player 2 could be converted into player 1. because in one of the objectives it says to go to the near by village. but the village is already revealed. so you should change the first mission. And if you know how to make cinematics, then you should create one and put it as an intro.
The reason why i didn't gave you a rating is because this map isn't finish. So when you finish it, i might give it a rating. But so far, I think you are doing okay.