Short input mode is intended for accelerated input of details using the keyboard without using the mouse.
If you hover the mouse over the "?" sign, you can see a hint on the "hot" keys:
When switching the edge with a space, the system highlights the cell with color according to the thickness of the edge.
From above, you can see which edge is selected (each edge has its own number and only it glows in the cell).
Also pay attention to the color of the triangle to the left of the edge number - if red, this is a curved edge, if blue is straight. If the font is bold, italic and underlined, there is a joint on the side, if the font is simple, there is no joint on the side.
