- The snaps on the dress should go according to the plan for sewing the petticoat and the belt. For the 4 color sensor connections, you should align the positioning of the petticoat snaps to their position on the inside of the dress, create direct lines from them to the back side of the belt connections and verify the lines don't intersect.
- Plan where on the dress you want to put the on/off switch and align the connection to the remaining 2 magnetic snaps.
You can use ribbon to cover up the thread lines. Therefore you don't need to sew from one snap to other, rather leave the thread flat with some extra room for flexibility. For each connection, start with the petticoat matching snap, sew that on with conductive thread, lay enough thread on the dress and sew the other side of that connection to the back side of where the belt snap will be.
Sew on ribbon to conceal the connections and keep them separated.
On/Off switch - using another pair of conductive snaps, place a decorative button to connect 2 snaps in a relatively convenient place on the dress.