Gather saplings from leaves or buy them from villagers
Choose a suitable open area with enough space above and around the sapling
Place the sapling on grass, dirt, podzol, rooted dirt, or farmland
Make sure the sapling has enough light to grow
Wait for it to grow naturally over time
Use bone meal on the sapling to speed up growth
For large trees, plant multiple saplings in the correct pattern if needed
Keep the area clear of blocks that could block growth
Harvest the grown tree with an axe or by hand
Replant saplings to grow more trees