Hi - welcome to the discussions!
The resume function is pretty simple as scripts go, but it is important to know why you need to use it in a script, since a lot of resume information is automatically stored and can be actioned in different ways.
For example, playing a track and pressing the menu button takes you to a menu. Pressing it again takes you back to the track - a resume.
Resume info is only stored if a track has played. If you go from a track to a menu, then on to another or subsequent menus, pressing resume (or menu) will take you back to the track again, even if it was in a different part of the DVD.
Similarly, if the track had finished playing, the resume function can give different results, some of which are unpredictable, depending on player functionality. You can resume back to the beginning of the track, to the end jump (and hence a menu) or nothing will happen.
So, knowing these things, the resume function in a script is easy to implement. You create a script, which gives you a single line (with NOP in it) in the script editor. Click on that line and look in the property inspector. The drop down list at the top lets you set different commands, one of which is the word 'Resume'.
If you save this script, with just one line, and point a menu button at it, then the disc will look for the resume information and attempt to complete the resume function.
So - why do you need to script this? Is any of the automated functionality going to be of use?