It will work only if you have more than 1 launch base.
The first base, give it frequency of 1
The second, give it frequency of 2
The third, frequency 3
and so on...
Now you need to tell the game from where and to where your rocket should go.
Example, if you want your rocked to go from base 1 to base 2: give the base 1 the destination frequency of 2. If you want your rocked to go from base 2 to base 1, give the base 2 the destination frequency of 1.
Launch when: change it to Cargo is loaded or 10 seconds or 30 seconds.
Place the rocket. Fuel it up with Fuel loader. Right-click it. Load it. No click on "Launch" button. Wait. Lift off.