Practice typing using your index finger for certain keys, not all of them. It is located next to your thumbs. It is your pointer fingers.
You must only use the left one for the letters f, r, g, c,v, r, t, b and numbers 5 and 6. The right one is used for the letters j, u, y, h, n, m,7, and 8. Never use it for other keys.
Before you start typing make sure your four fingers on your left hand is on asdf. That is your pointer finger on f. Your middle finger on d. Your ring finger on s and your little finger on a.
Fingers on your left hand should be on ;lkj. That is your index finger on j. Your middle finger on k. Your ring finger on l and your little finger on ; this is the key after the letter l.
When you have to use each finger raise the other three and only press the one that you are using. So the pressure will only be on just that one finger.
Also make sure you are sitting in an upright position. Your back straight, feet flat on the floor, fingers raised and touching the keys. Your hands should not be touching the keyboard. Only the tips of your fingers.
Take your time and start slow.
Here are some practice exercises for each letter and number:
Using your index finger on your left hand practice typing these letters 5 times each until you can master them.
Now using your right index finger type the following letters until you feel comfortable using this finger. Five times each.
How was it? It really feels good using the index finger the right way. Keep up and you will be able to master each of them.