To import into your scene go to File>Append, navigate to .blend files folder, open the file, open "Group" folder, then double-click on the name of the group and append.

The name of the model and the name of the group is the same.

Or you can select it and copy it using CTRL+C and in your scene pressing CTRL+V.

Please note that this scene contains textures from Johny Mrázko  - Textures may not be redistributed

The model was created for Cycles, if you want to use it in Eevee please set Alpha to Hashed in material options. 

BUG: Models were made for Cycles in version 2.79 and in some versions 2.8 and higher (we will specify which exactly) there can be a bug, where for no reason leaves are changing color randomly. We want you to enjoy our models without problems, that is why we offer you a simple solution. Disconnect the bottom part of the node tree if this problem will appear in your project.