You don't write script for Apollo. Everything start by hand, however, what you did was stored in a command log file. That's the script you can use to run again .Basically the command syntax look like a scheme language ( a dialect of Lisp). You can find everything you need from SOLD
Yes, when you are building up the low first time. You can use the GUI (it is always needed). After the flow is built up, you just need to modify the command log and freeze the flow. Only some parameter need to be modified when do another projects.