TDDFC

Hey there, Sorry for the post but I'm a noob to 3d printing. I was setting up Cura on my computer and noticed there was an option for the Ender 3 and Ender 3 pro but nothing for the max. 2 questions, 1 what is the best option for me to select for my printer and 2 how do I set my bed size. ( 300x300x340mm) thank you and sorry again. TFC