A Beginners Guide is a guide for beginners, and it could also be called a a Beginners' Guide, if you like apostrophes. Call it a Beginner's Guide and it's a guide for one beginner: if there were several beginners then they would each need one of such a guide. Now this class is for beginners.
Or for lots of beginners - hence a beginners' class? Or is "beginners" an attribute of the class - hence a beginners class? The question was discussed at length in an other thread about a woman's college, and baby oil came into it as well. As the themes are so close, I'll move this thread to the end of the previous one, and change its name.
Possessive - Woman’s college - Baby oil - Beginners class - singular ...
Are they going to teach English to beginners? They might be sitting at their desk in front of the class for much of the time, or standing writing on the blackboard.
At any rate, beginners are usually looking for an approximation in their native language...and this analogy is helpful. These speakers develop further accuracy through practice and contact with native speakers.
Is there a good resource (course or book) for transitioning from Homeric to Attic without having to do yet another full blown course? Clyde Pharr, "Homeric Greek", is a textbook for beginners. In the appendix he has an outline of the major differences in Attic.