Menu > Project > Project Options, then the "Forms" category on the left.
Here you can move forms around using the buttons (with up/down arrows icons). When the program starts, the first form in the list opens.
In fact, you can manually swap the lines with "CreateForm"
Just don't move a form to another list (left/right), otherwise it won't be automatically created on startup (by default, all forms are always created, but all but the first are hidden).
Although I'm not sure how this works on Android.