She's still very young. I would not force her to jump yet. On most of the grids, there is no 'real' height on the jumps.
Which DVD did you order? The puppy jumping or the foundation jumping? I have not seen the puppy jumping DVD myself.
The 'low jump' in front is actually not a 'jump' - it is just a marker per say. The V-apparatus helps with the dog's ability to jump into the set point area and out again. It will come with time. The good thing that Susan said at the seminar, the young dogs don't have any bad habits of us teaching them how to jump, so they pick all this up very quickly and easily. So don't worry to much if she is walking through it. My question to you would be, what kind of a treat are you using on the target? If it is not enough of a high value treat, the dogs aren't as motivated to get to it quickly. Also, if she is young and therefore small, what distance do you have between the two 'jumps'? If it is too far apart, she will not be able to get one bounce/stride in the set point. It sounds complicated but it is not really. When you get the DVDs, the first DVD explains all of it really, really well.