Hi,
There is a lot of potential for creating dynamic forms with LC. The help file in LC and the guides on the Adobe web site give a lot of direction.
In your first field you can write javascript against an event, in this case the exit event is probably best:
if (this.rawValue == "" || this.rawValue == null) // this is a test if the first field is empty
{
textField2.presence = "invisible";
}
else
{
textField2.presence = "visible";
}
When testing you use double "=="; when assigning values you use a single "=". TextField2 is there, just hidden from the user.
Good luck,
Niall