There are a couple of ways of having the driver blow his horn before moving. The easy way is to use the Hornz driver command.
Place one Hornz command in before your track mark you want the driver to go to in the forward position. Place two of the commands before the track mark you want to drive to in the reverse direction.
The hard way is to use a scripted horn sequence. This is done via triggers and scripts, and it's not difficult though to get things working how you want them can be a bit complex.
The locked knuckles should happen if you clicked on the decouple then couple. The railcars should lock and be ready to move along. Some rail cars, such as those by Dave Snow and the Jointed Rail guys for example, have animated couples which will move the glad hand brake hose into position, which indicates the couples are coupled up and the consist is ready for driving.
And finally. There are two ways to save your driver commands.
1) Edit the session and edit the driver schedule.
Here you put in your driver commands in the same fashion as if you were setting up the drivers n Driver.
2) The more convenient way is to use the Schedule Library.
With the Schedule Library Rule, you include this in your session setup.
You then add your command in the same fashion as above and then save the schedule and give it a name.
Now when setting up the drivers, you then use the Copy Commands from driver command. You choose insert and from library where you will see all your saved commends.
This is particularly useful when you have a lot of consists and AI drivers setup and all follow the same or nearly the same schedule. With these saved commands, they can be copied and things can be changed in the Schedule Library, and the commands can be changed during a driving session, however, the changes are not saved and need to be implemented when editing the schedules in the Session editor.