The tools for stretching the ears are simply tapers and tunnels.
To make it real simple.
Tapers look like long thin spikes starting small at one end, increasing in diameter / width at the other end.
With enough force within safe limits the aim is to push the taper through the ear, stretching the tissues SLIGHTLY past their normal resting state.
This is STEP 1.
Now, once this is achieved and it isn't pushed too far risking tearing, the taper is left in the ear for 1-2 weeks, sometimes longer (longer the better for safety),
This is STEP 2.
If you want to keep increasing the the size / width of the opening, once the tissues have healed you can move to the next taper size up.
This is repeating STEP 1 after tissues have healed from STEP 2.
You can keep repeating the process until the desires size is reached.