Stopping Overlapping Windows

This is the 3rd apple product I have purchased, this Mac Desktop being the only 'non portable'. To be frank, It is quite strange getting used to the new set up and just how things work here in general. One thing I am looking for a solution for quite eagerly is how, for example, I am working on a document, writing etc., when I receive a text. I click the notification when it opens a whole new window, pushing everything else to the side so I see the desktop background with only the iMessage tab open in the center. Is there some kind of way to only open this tab up on top of whatever it is I am working on?