Good monring all,

I'm fairly new to cake decorating - took the first two levels of the Wilton classes approx. 1 year ago...haven't learned about tiering cakes yet...when making a tiered cake is each tier supposed to be layered?

yes.  Unless you're doing a design that calls for a short tier.

And I'm sure you'll get answers that say to do whatever you want, but traditionally a tier is two layers.  I torte each layer, so my tiers are four layers each.