Its been a long time since I drove a car with a cruisomatic, but... by my understanding and memory. They start in 2nd gear, you don't really need 1st, at least that seemed to be Fords thinking of the time. Howerver, you can get and hold first by pulling the gear shift down, into 1st after you start moving.

Then you will hear the 1, 2, 3 shift. Under normal conditions you will only hear/feel 2nd and 3rd. There were later model (FMX ?) shift kits or modules that will let you select and shift 1, 2, 3, but I really don't remember which car/truck was the source. There is a web site ...I searched for it and posted it here several times... that details the buildup and parts to put a strong Cast iron cruisomatic together using a middle size (passenger car) case. The cast iron cruisomatic came in 3 different size case formats. the largest was used behind Lincolns and some trucks.