Hi,
There is no automatic way to populate them, but you might find this helpful:
- you can multiselect your extensions, edit they BLF section once, and it will apply to all extensions.
- or you can also create a template extension that contains all the BLFs you want, and whenever you want to make a new extension you can use the "copy" function to make a new extension that contains them.
Note: Not all handset sidecars are the same, for some the first BLF on the sidecar might start at a different position than other models, you need to check this yourself and see on your phone model / sidecar combo