You really shouldn't miss class at all, but if you do be sure to email your instructor and try not to miss an entire day! If you do you will end up being 8 hours out and most teachers will fail you for that or anything over that. You may be able to make some of those hours up by staying late or coming early but again that depends on the teacher that you have. Keep in mind when you miss a class or are late to a class you lose GPS points (See blog about GPS points).
Being late..
Try not to be, most teachers don't care if you show up a minute or two late but if you are much later than that you can be counted 2 hours out.
Play it safe and don't be late and don't miss a day of class!