The available manuals are not up to date. The user interface has been quite rearranged. So just seek for the wanted command at other places. It is somewhere. For instance the drawing setup now is under "Options". Go through all the menues to get oriented. The way the commands work is the same.
What do you mean with drawing a line doesn't work properly?
I have added two templates, one in mm and scale 1:1 for mechanical parts, and one in cm and scale 1:100 suited for architectural drawings, both for A4 size, as usual printers only go that far. It makes it easier for a start, open them, draw around in them and study the settings.
mech_mm_1_1_a4.dxfarch_cm_100_a4.dxf