The Left Hand
The left hand holds the steel bar, sometimes called a "tone bar". The bar is held perpendicular to the strings. Make sure it doesn't slant or your playing will be out of tune.
The middle finger rests in the corner of the bar and the strings on the left side of the bar. The ring finger and pinky rest on the strings behind the middle finger. This is important because if the ring finger and pinky are lifted, the strings will buzz when picked. The index finger rests on the top-right of the bar. The thumb rests against the right side of the bar. Avoid letting the thumb touch the strings to be played.
The bar must stay parallel to the frets. Any pivot will cause intonation. Make sure the fret line is directly under the bar no matter where the bar is at. There is a tendency to have the bar a little to the right of the lower frets and a little to the left of the higher pitch frets. This is due to the player's perspective of where the fret line is. Avoid this. All this will take some practice at first but will become natural with time.
Left Hand Exercises
Here are some finger-picking exercises with bar movement. Always use a metronome. Start slow and gradually work your way up to faster tempi.
Notice the finger picking pattern in each part of exercise 5 is different. Try the first one with just your thumb. Practice it slow until you become precise with the bar movement. The bar should be exactly over each fret as you move up and down.
Once you can move the bar accurately, try the next two parts of exercise 5 which require alternate picking. Remember to block after each note in these exercises. We don't want to hear the bar slide from one note to the next at this point. Each note should sound distinct like you were playing it on a piano. Remember to use a metronome.
Now try Exercise 5 in reverse, that is, start at fret 13 and move towards fret 1.
Even though the fingering for T-M is not marked below, do both exercise 6 and 7 with both the T-I and T-M fingering patterns.
Notice in exercise 8 below that you have to use the middle finger in the second half of the exercise and then use your index on the last note before repeating the exercise. This ensures that you are always alternate picking. The idea is that you do not want to have the same finger strike the same string twice in a row. This will slow you down as you try to learn fast phases latter on.