First of all, be very careful to do your Queue. Make sure it is the next thing you want sent to you, because they are set to mail them automatically, often before you even realize it. So many times I've had my mood change & meant to go back to change the order of my Queue, but then get something sent to me I would have rather changed. So you'll want to get into the habit of making sure the first 5 choices or so are definitely something you want to watch right away.
They will likely send you the first dvd as soon as they successfully bill your credit card, or in this case, confirm it is a valid card & process your new account. I don't think you have to do anything else at this point.
Another tip: make sure you have the scan code showing in your return DVD, because they scan those at the post office & send you your next selection very fast, that way.
Hope that info helped; enjoy your movies!
☼SerenityNow!☼
"Be as a bird perched on a frail branch that she feels bending beneath her; still she sings away all the same, knowing she has wings." ~Victor Hugo