Just use a text editor. if all is normal you already have a bw_shp13_smart_plug.json in the “devices” folder.
If you have HA or other docker OS How to add/edit a DDF on Home assistant using text editor? - #2 by Smanar
For normal OS
All DDF provided directly with deCONZ typically reside in
/usr/share/deCONZ/devices/on a Linux system and are loaded first. However, files residing in the home directory of the user running deCONZ (e.g./home/<DECONZUSER>/.local/share/dresden-elektronik/deCONZ/devices) will override the pre-packaged files to allow users to amend and keep their own files if desired.