Thank you for those suggestions Alvin - -I will try them.
I saw that Pick Point Hatch and PPH-ing are two different things but could not understand the manual's vague explanation. Another respondent yesterday suggested using that. I tried it, and it seemed to work, partially, but only once then not again.
To your other point...
Oh, I know it's me not the software at fault, although it and its manual do you leave you floundering.
The more I try to advance with it, the harder each move becomes, and that's why the suggestion that showing cross-sections needs a 3D drawing, is so disheartening. It's like being waist-deep in the shallow end of a full-length swimming-pool full of treacle, where the 3D skills are at the deep end.
In advancing what should still be straightforward technical drawing basics, the more complicated, difficult and un-intuitive the computer-driving. People talk of learning things in small steps. TurboCAD's are staircase steps, each bigger, more difficult to climb and more slippery to stay on, than the previous. This still at very low level: I do not envisage being able to reach the skill of the draughtsman who made the two 3D illustrations on my software copy's physical package. (Of two different sub-assemblies. One is what I think is a 'wireframe' image; the other, fully-coloured solid.)
In this case, learning from you all that I should really be using TC's 3D functions, does not put a few small steps in front of me, but those TurboCAD steps on a very high, steep, winding staircase to floors I cannot see.