How to deal with newly created files and preselected items?

[SkyFrontier]

Can someone please give some hints on how to:
-produce new items via copy/move/backup/new and later get them available for a posterior script action?
-how to apply a "selection container" and (same matter) later get the originally selected items available for a posterior script action?
Each and every time I try to attribute a value such as "$pack", the whole thing stops telling me that no files were selected for the next action.
Thanks!

[SkyFrontier]

"Nothing selected in the file list".
"No file(s) selected".