If you bed is part of the slide out, and you were to open the bed box you would find a hydraulic system that is used to open and close your slide. I have seen where a couple of people have modified the top half of their box so it would open and close and be used for storage for things like shoes etc... but you won't be able to use it like your last bed.
The bench seats are your primary lift for your garage bed system. Take the bench seats all the way up until it automatically stops right underneath the queen bed. You will find 4 pins (one at each corner). Pull these pins and store. Press your switch to lower you bed assembly down. At approximatley the half way point, the queen bed will stop and the bench seats will continue down. If the queen is still to high, you might have a little room for adjusment. I you look inside each rail, you will see a plate which is used to lock the queen bed at that point. If you adjust one, ensure you adjust the other 3 to match. Ours was able to be moved down a couple of inches. The small holes drilled into the rails dictates where you can set your plates to stop the bed during lowering for use. We found us a nice folding two step stool that we use for anybody that wants to use that bed along with the DW when she needs to reach a cabinet that is to tall for her... Hope this helps!