ConS, Con1, ConE…) are learned from your own annotations, not from a built-in table.
If the chain has a gap, the cassettes that start where it stopped are offered below the slots — including the spacer fillers.
Search by annotation in the box above to find a cassette by what is expressed in it. A hit goes into the first slot its left connector fits, or a new one at the end.
The map shows the assembled construct; each junction keeps its connector barcode in the exported GenBank.