Answer:
First, make sure that the line grid is not locked. To do this, right-click in an empty area of the work window. If the line grid is not locked, there is no check mark in front of the "Lock Line Grids" entry (Image 01). If this check box is selected, left-click the "Lock Line Grids" entry (Image 02).
You can then copy the line grid using the "Move or Copy" function. To do this, select the line grid first. Then, open the "Move or Copy" dialog box using the menu Edit → Move/Copy or using the corresponding button in the toolbar. Then, define the number of copies and the displacement vector (Image 03).
As an alternative, you can copy a line grid using drag & drop. First, make sure that the "Enable Drag & Drop" function is activated. To do this, right-click in an empty area of the work window. The "Enable Drag & Drop" option must be activated in the shortcut menu (Image 04).
Left-click the line grid to select and drag it to the desired location while holding down the left mouse button and the Ctrl key. As soon as you release the mouse button, the copy is created at the location.
The video shows how to copy a line grid using the "Move or Copy" function. Subsequently, it shows how to copy using Drag & Drop.