To me a welcome letter should be short and to welcome your person.
You don't want to scare them by piling up a lot of information on
them all at once.
Let them know that you are glad that they are on your team and that you
are there if they need help.
You can mention a couple of things they can do to start off with but
these people already have a ton of information to go over so don't overload
them.
