When I went from AB to siemens, I think I had a few areas that I needed to get up to speed.
How do you configure hardware? Is there certain issues to be aware of such as hardware/software conflicts? In AB the software/firmware moved in lock step in CPR releases.
How do all functions relate in AB to GE? What is the same what is different? Is there some basic knowledge that is fundamental to understanding the function? I know in siemens if you do not use the function at the scan time you have to jump over it, this was different from AB.
Specialty cards such as RS232, Ethernet, controlnet(AB) vs profibus (siemens) (what is the standard in GE?) How do these cards work?
Of course if you can get a GE processor, see how you upload, download, change code online, offline. How do you download firmware to different cards? Can you get online thru RS232, some protocol that GE has or can you get online thru Ethernet?
Gather all the pdfs on GEs in a library on your laptop. Nothing worse than not having the manuals when your doing a startup.