A beginner making a mistake ...

I come from F360 where a drawing (ie: triangle) is simple. Connect lines while letting them snap into place, then they highlight as a profile, ready to be used for a Revolves, Extrusion, etc.

When I do the same in SW Design, the lines snap into place, but the  result is an un-usable shape. It does not highlight in the color blue so it can be a Revolve, Extrusion, etc. I thought the lines might not be connected at the points, but that does not appear to be the case when I zoom way in.

I know there is something called Construction Lines, but the boxes for CLs are always unchecked.

Any constructive help is appreciated. 

TIA