You need following:

- a plant (tree or fruit tree)
- a spade
- some water
- a hammer and four wooden sticks (if you want to protect the plant)

 Make a square with a spade

Cut it in half

Take both halves out

Pour some water in the hole
If you plant a fruit tree, you can put some quality soil on the bottom first.

 Put the tree in the hole and pay attention to the level of it

If needed, add some soil under the plant, so that the plant is at appropriate level.

 Cut lower part of soil from the halves you took out, if needed, so they fit properly.

 Put them next to the plant and press them strongly

 Collect the soil that left and water the plant

If you have a pet, you can hammer down some sticks around the plant and protect it from being broken. 

If you have more trees to plant, you do the same all over again.
You can make your own park or orchard if you have space and if you like trees.