Good news! It couldn't be more simple. You just take that sap and put it in your mouth. That's it.
I shed a tear when I think of all the precious opium that has been wasted by people trying to turn it into something smokable when they could have just eaten it for great effects. There's this very strong, historical and cultural notion that opium is smoked, but the vast majority of people who are just growing a few cheeky plants are better off eating the sap and/or making tea from the pods.
It's the KISS method (keep it simple, smoothbrain)