Haskell Recursive and / or Tree

Please build it on this: data Tree = Leaf Float | Gate [Char] Tree Tree deriving (Show, Eq, Ord) and write for beginners

In the first part of this assignment, given a list of probabilities and a list of logical operations, your program will find the probability of the top event (see Fig.1 For simplicity, we also assume that there are two types of operations on the probabilities: OR and AND gates