@Fritz2017, I've never had seeds on my plumeria, but we have some very good plumeria people here who will soon have an answer for you. I've suggested moving this to the plumeria forum for quicker help. https://garden.org/forums/view...
Once the pod has started getting hard (usually 9 months on the tree) you can place a stocking / pantyhose over the pod so that it still gets air. The pod will open slowly and start to release the seeds. Once I see that the pod has cracked open I will start gathering them.