you mention "attach"
try UNchecking "attach" in the task bar at top.
things like beams and posts will attach to each other UNLESS
you uncheck "attach" not sure of all the things that attach.
note:
you can use beams, posts and other symbols to create some neat things.
pergolas, trellis, and so much more
note: check out the 3d warehouse (sketchup) for 1,000's of great 3d models
like the tomatos, grapes and other vines.
you download them and import them into softplan or any folder you want
and them use the symbol wizard to make them useable with softplan
as 3d/2d symbols and put into your "symbols" libraries of choice.
https://3dwarehouse.sketchup.com/
download and import them into softplan /3d symbols (or other ways to save them)
and turn them into re-useable 3d symbol in all your future projects.
beams: not the curve at end of beams / you do that in softplan with "profiles"
when editing the beam / hit the "bean end tab" and add any custom profile you've
created or use one of the pre-created ones that are more common in construction.
btw, you can use one of softplans many predone brackets or corbels or create just about
any custom design you desire.
the more intricate curved/rounded corbels are best done in sketchup.
softplan can draw almost any brackets you'll ever need or want.
left click to ENLARGE image below:
trellis spoke bracket cross beams tomato vines.JPG