I would not expect MS Word shortcuts to work in Arbortext Editor. If you don't see the Table Editor toolbar, you need to check your preferences and turn them off if your copy of Editor. If you still can't turn them on, it may be that your IT group has made it so you cannot do these kinds of markup changes in Editor. You will need to talk to whoever is managing your local implementation.
We have a cheat sheet of all shortcuts available to our customers; if you would like access to it, you should sign up for the TC Dojo Mastermind Group (http://www.single-sourcing.com/products/tcdojo/pricing.html)