Passing parameters from form to controller using RoR

I am new to RoR development and am a little confused about how parameters are passed from a HTML view to the controller. I have seen a few examples online which use a private method like this:

private
def message_params
  params.require(:message).permit(:content)
end

I have been looking for some clarification online as to what this method does and how it works, but I only encounter posts/articles which use the method rather than explain what it does.

I was hoping someone could explain how the method takes(/filters?) values passed via the form via a POST request, what the require and permit keywords mean and how would i change this method to fit my own use.

For example if i needed to get data about a new book would i do this:

private
    def book_params
      params.require(:book_name).require(:ISBN).require(:Author).permit(:Illustrator)
    end

Would the above be valid given that my book object has those fields?

Any clarification would be appreciated.

Thank you.