Pick a unit with transporter inside. Click "use this unit to do a paradrop" and the game will lead you further.
Typical range is 10 hexes if the transporters have full (100) Action Points.
Are you positive about the this "pick a unit with transporter inside"? I am able to do the paradrop, but I have to have my paradropers as a separate formation. It doesn't seem to work when the paradropers are actually within a formation containing a transporter.
Anyhow, I must be low on AP or fuel, 'cause the times I've tried I've only been able to paradrop three hexes.
No, the paratroopers must be in a separate unit under the transporter. When you click on the transporter and tell it to do a paradrop, it asks you to choose the paratroopers.It works the same as loading ships.
Definitely need to be in a separate formation. Why I'm not sure. I would think you should be able to load paratroopers while inside a formation with only transporters.
But I was simply low on APs. Once I had enough, I was able to paradrop 10 hexes. Didn't do much good, as my paratroops were wiped out a turn or two after landing. Engineers can be paradropped, too.