Well no one seems to have said welcome, so welcome!
As suggested earlier, get reading into the threads in here and you will probably find that all of your questions have already been answered - if they haven't, then you can always come back in with specific questions.
You already have a good start because you have got past that stage of asking "which bike"!
Sooner or later, those in here who own an Africa T will answer up and give you some advice; you can do a search in here using any key word that appeals to you, BTW.
You could also consider looking into the web for specific sites dealing with the Africa Twin (often known as the AT or @).
The basic choice on luggage is soft or hard; read up on both!!
Oh yes, they say that the reg/rec is a weak point so you might want a spare one for travelling,