Mango trees are easy to grow from seed, but you must live in a tropical climate. Many mangoes are hybrids---their seeds won't produce the same fruit as their parent. A seed-grown mango won't start fruiting until it is eight years old, whereas a grafted tree will fruit within three to four years. If you're not in a hurry and your parent tree is a "polyembryonic" variety, start mangoes from seeds.
Remove the flesh from a mango by eating it and then wash the remaining flesh off the large seed by scrubbing it with a soft brush.
Allow your seed to dry in a warm, dark, dry, well-ventilated area for one to two days.
Cut the seed open lengthwise, along its seam, with a knife. Remove the small seeds that you find inside. They should be white---if they appear shriveled or brown, discard them.
Plant the smaller seeds 2 inches deep at the beginning of your rainy season. You can plant them in a sunny location where you want them to grow if you want, making sure you leave sufficient space between the planting area and other trees, your house, garage or other building, because mango trees grow very large. Dig compost into the planting area to give your tree the nutrition it needs. Water the seeds well after you plant them.
Alternatively, plant your seeds in pots, using standard potting soil. When they are one to two feet tall, transplant them to their permanent outdoor location.