When you buy a tree from a nursery there is usually a stake attached to it. That stake is in place to help the tree trunk grow straight. However, the stake also prevents the tree from building stress tissue which gives it strength. So when you’re ready to plant your tree you’ll want to remove the stake, but keep it on hand because it can still be useful.
Once your tree is in the ground, grab that stake and push it into the ground at an angle near the base of the tree. Bring the stake across the tree, keeping it straight. Then tie it to the tree with a plant tie. The stake will help keep the tree from blowing over, but will still allow the tree to move. The plant can move back and forth which allows it to build the stress tissue the tree needs to get stronger. After a while, the tree will no longer need the support of the stake.