It's no problem if you can't make the Pre Departure Meeting. Just let Africa Travel Co know, They'll send you most of what they speak about in a Pre Departure document when your tour is confirmed to you.
As you will miss the Pre departure meeting it's recommend that you pre-book into the Pre Departure Hotel for the night before the tour starts, so that you at least don't have to worry about taking a taxi to the departure point the next morning but are already there. You will also need to pay your Local payment to your tour guide the morning of departure instead. Remember to bring this in US$ cash.