Joints

I’m a newbie at Joints. Goal is to create plane, and wrap plane around cube like wrapping a gift.

I understand and am able to set up a plane, create joints and fold plane to form 1st part of cube.

What I do not understand is how to add additional joints perpendicular to start folding, tucking the left and right sides to enclose the sides of remaining open ends of the cube, which involves triangular folds.

I have set up the joints, but don’t know how to get secondary, side joints to be part of main joints.

Thank you for your help Cineversity!