Scisnap Graphpad, need help to input a directed graph

In SciSnap's Graphpad, how does one specify an edge to be directed? If I specify the edge to be directed, it has two-way directions, I want to be able to specify one direction. Such as an edge p->q, rather than p<->q. I am quite sure there is a way, but I could not figure out how.

Thanks in advance for any help you can provide.

I figured out by looking at the final example on the family tree.