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

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

Buttoned_Sofa_Single_Blue_Leather

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

HDRI maps are from HDRI Haven