Golden Apple is native to the Indian sub-continent...grows throughout the caribbean. It is also known as July Plum amongst West Indian Immigrants who live in New York. Not aware of size of dwarf specimen but normal variety can reach 40' tall and has a massive root system.
Planting instruction: What you have is a single seed...Plant in a good potting medium. Cover with 2'' of soil and start in a 8" pot. Maintain minimum temp of 75 deg. F. Germination takes 3-4 weeks maybe longer. Allow potting mix to dry out between watering. Good luck and report on progress