With Enscape 3.5, we introduced the multi-asset editing feature, which allows you to select a large group of assets at once. Please note that this feature is not available in Enscape 3.4 or older and currently only available on Enscape for Windows.
In the Enscape window, make sure that the Asset Library is open (by clicking the button in the toolbar or by pressing “L” on your keyboard. Press the “Shift” key on your keyboard and then left-click and drag your mouse cursor. This will enable a rectangular selection box - any assets within this selection box will be selected.