Sorry in advance if this question is excessively noobish or seems lazy. I have no engineering background and am unsure where to get started tackling this problem. Links to resources that could put me on the right path would be very much appreciated. I'm not looking for others to do my work for me; I just want to know what sorts of calculations I need to do.
I'm looking to build a cube-shaped structure, roughly 10 ft cubed, for suspending a series of seats (swings, sort of) for people to sit on. I'd planned on building the structure out of 12" aluminum trusses or buying one pre-made. Here's an example of what I might buy or try to build, for visualization.
I'd then loop rope around the horizontal trusses, using the rope to hang "benches"/"swings" from the structure. I'd attach the trusses to plates and use rebar to affix the plates (and the structure) to the underlying ground.
So the question is -- How do I test whether this structure would be sturdy/safe?
If I'm planning on hanging, let's say, five seats from each horizontal segment, how can I calculate if the trusses would support that sort of vertical force?
How about the horizontal force caused by someone potentially swinging on one of the seats?
Horizontal forces caused by wind hitting any tarp (solid or perforated) I use to cover the structure?
If this calculation is too complex/multivariate for an amateur like myself to reliably tackle, is there somewhere I could turn for an engineer's feedback?