it is enough not to close the edges using the creation option of the lembi with fold that starts from the edge or by activating the cut of the edges.Now I'm not in front of the cad but, if you want to make a box like the one in the annex, I guess the connection is to not make the edges of the first series of "multiple edges" coincide? I don't know
does not close with such command. It gives me "unsuccessful operation"if it was necessary you can then use the command close two fold corner