(2020-03-20, 9:18)Lidong Wrote: How to open this interface? Thank you
It's a split view. You can apply that by using the options in the top menu bar's view menu. Then select "editing view" and then "split".
The layout in the picture uses a vertical split, with a horizontal split in its right side.
When you got the 3 views you can change the right ones to 2D using their compass in the corner (click the 3d label)