when the seed pods turn black the pods are ready. pull them off the plant and then the pods will pod open. the seeds are like sweet pea seeds. I sow mine in February 2 per 3" pot.
hope this helps.

I am going to try this year too. I will sow them in pots in stages, some in Feb some in March some in April just to see how things go.
I will leave some pods on the plants as long as possible to collect seeds ; till they go black and even a bit crispy too.