When you place a feature (tree, road, building, whatewer) LOCK IT (L key)! Every single one. Lock lock lock and lock. Take care that what you want to lock is selected (white border). Otherwise you UNLOCK the table, throwing everything around. Furthermore... SAVE SAVE AND SAVE!
I know, I'm not expert, and surely there are more elegant ways, but this is what I do.
Think of it as putting a box of fragile figures and vehicles in your car, but without securing them inside the box before driving off.
Did you sign up for Virtual Lard 4 on Discord? These events are ideal for teaching new players. You might be too late now as there were over 100 applicants for the 80+ places, but you could always check. The event is being run by a splendid chap called Jeremy.
