Ten finger typing relies on the memorized position of keys, but once you have practiced enough, your fingers will type without you even thinking about where your fingers are going or about the position of the keys.
The essence of this method is using all ten fingers to type, and to achieve that, each key on the keyboard is associated with a specific finger. It also requires that your fingers are placed in a specific position, which is usually called basic position. When no typing or after pressing a key your fingers should always return to the basic position.
To know where to place your fingers, feel the bumps of the F and J keys. Those bumps are there to guide you to position your fingers on the keyboard without looking at all. Place your left hand index finger on the F key and the right hand index finger on the J key. The other fingers should be placed on the keyboard as shown in the figure, but they should only lightly touch the keys.
Left hand: little finger on key A, ring finger on key S, middle finger on key D and index finger on key F.
Right hand: little finger on key ;, ring finger on key L, middle finger on key K and index finger on key J.
Thumbs on the SPACE key.
Depending on the key to press, we move the responsible finger to that position, press the key, and then return it to its basic position.
The following picture shows which keys are responsible for each finger, depending on the side they are on the keyboard.
The thumbs are responsible for pressing the grey keys (the SPACE key and the two adjacent keys), little fingers are responsible for pressing the yellow keys, ring fingers are responsible for pressing the blue keys, middle fingers are responsible for pressing green keys, and finally index fingers are responsible for the red (left hand) and violet (right hand) keys.
Learning the position of the keys and which finger is responsible for each key is critical to learning touch typing, but the daily practice will do the trick, to the point where you won't have to think about it. Practice bringing your fingers into the basic position without looking and then away. Repeat until you can do it comfortably.
It might be difficult at the start to use all fingers, but as you spend more time practicing, it becomes easier and faster.