Can't work on linked models

I made a tree in one file and linked in the second .blend file. The tree came out but I can not scale it or move to another location of the scene.
Someone know how to solve this problem ?
Please Help !

Object > Make Local > Selected Objects

Just so you know, its not a problem, its the expected behaviour.

You should have appended if you want to further edit the object in another file.

You need to link in objects using Groups. You’ll be able to scale and move a linked group instance.

Thanks a lot !

Blender - Connecting people.