documentation needs to be before the method and the name should be mentioned last and it should be FirstName M. LastName and each part has to be separated by sentences ended with periods.
Check this example:
# This is a silly function that adds two things.
# x - addable.
# y - addable.
# Returns x + y same type as x and y.
# Time complexity: O(1).
# Authors: Ahmed H. Ismail, Ahmad H. El-hamshary.
def add(x, y)
    x + y
end