Haskell Tree Structure Explanation

Im currently trying to write a minimax algorithm using tree in haskell for a connect four game where it takes maximum tree when its ai's turn and minimum when players. I've tried to find how use the tree structure in general such as : create, write, read and traverse however the internet returned with no helpful result as I'm declaring the tree in a specific way

The Tree structure that I'm implementing is defined as follows

data Tree a = Node a [Tree a ]

I understand how I can create a tree variable like

t :: Tree Int 
t = Node 0 [Node 1 [], Node 2 []]

But i do not know how to actually use it or manipulate or access the node's value
please prodvide any or all examples and explanations

Thanks

To access a tree value you use pattern matching, often together with recursion and/or other library functions.

For instance, let's sum all the values in a Tree Int.

sumTree :: Tree Int -> Int
sumTree (Node x ts) = x + sum (map sumTree ts)

Here the tree value is dissected into the root value x and the list of subtrees ts. Then map sumTree ts recurses computing the list of all the sums of the subtrees. We sum that list of integers into a single one, and then we add x to conclude.

In this example we did not have to provide a base case, since when the list of subtrees is empty map does not perform any recursive call.

If you are new to Haskell, I recommend you study pattern matching in a tutorial like LYAH. It is one of the most important techniques to know in Haskell.