1. Launch solarus-quest-editor (in package solarus-quest-editor)
2. File->New quest...
3. Make a new directory for the quest, select that directory, click "Open"
A dialog pops up with an error like the following:
I believe this is likely because it recursively copies a template
from /share/solarus-quest-editor/assets/initial_quest/ relative to
the installed solarus-quest-editor to the destination and keeps
permissions.
-- -Jesse Gibbons