First of all, johnathan, at 13, if you are looking for instant gratification ... Orbiter is not it. You have to read and
learn. Make sure you read the Orbiter manual (mostly completely). Ask all of the questions you want, but if the answer is in
the manual, you may get a testy answer. Also, when you need help and ask a question, it is better for all if your subject
heading is reasonably descriptive. You may find you get a quicker answer.
Now to answer you as directly as I can ... it depends on the scenario you have chosen whether the DG3 is in it or not. If the
scenario doesn't call for it, the DG3 will not show on the available ships list. Just having it installed will not place it
on the ships list. To observe this, when you open Orbiter, you will find the available scenario list on the Orbiter
Launchpad. Doubleclick on the directory DeltaGlidedIII_2005. Then doubleclick on Mars Scenary and click on scenario that is
available there. Follow through on the rest of the tabs.
For a very useful training flight, download Trevor Johns Tutorial (available in Dan's Download page). Install it, read the
documentation that comes with it, select the Olympus Mons Spaceport scenario ... and have fun.