https://www.codingame.com/training/medium/minimax-exercise
The puzzle is academic and quite straight forward.
First things first, I want to solve it manually.
But I don’t understand how to find the expected for test 2.
Could someone show me at least the game tree for this one ?

Do you know minimax theory ?
depth 2 with branching factor 2 means the tree is
Root
A B
1 2 3 4

So you visit something like root -> A -> 1 -> 2 -> B -> 3 -> 4 (i don’t pretend that’s the right order)
ie you visited 7 nodes, and you can guarantee score of 3, because you play to go to state B and opponent then play to give you a score of 3

In the first test case there is a root node with 4 children.
The max score for the player is 3 and you need to go through all 5 nodes (root + children) to find it.

@Yatech thank you very much for clarification. I missed the second Branching factor parameter and imagined binary tree. Original task is missing such a text art as yours.