I don't know where you got the seed pod or how you have searched, but I'm not finding much info on how to germinate these seeds on the internet. I did a google with:
Pterocarpus Marsupium + germinate
and did find books referenced that might have the info you need. You could also try searching with:
Pterocarpus Marsupium + propogate
This site has some info that I can't view as I have cookies blocked.
I'm including the cached versions of these sites so you can better see where to look for the info. This first site is a book you might be able to find at a university library.
https://188.8.131.52/search?q=cache:X4c5I_VdfMEJ:https://www.vedamsbooks.com/no33653.htm ... =clnk&cd=6
This site lists your tree but the links aren't working. Maybe you could contact them. You'll have to scroll down for Pterocarpus Marsupium.
At this site these folks say they sell the seeds and have info on germination, etc. You might want to contact them to see if they will share the info you need.