home row finger placement, explained
Home row finger placement means resting your eight fingers on the middle row of letters — a, s, d, f for the left hand and j, k, l, semicolon for the right — with your two index fingers on f and j, and both thumbs on the space bar. Most keyboards have a small raised bump on the f and j keys so you can find this position without looking, and every other key is learned as a reach from home and a return to it.
where each finger rests
Left hand: little finger on a, ring on s, middle on d, index on f. Right hand: index on j, middle on k, ring on l, little finger on the semicolon. Both thumbs rest lightly on the space bar. This is the position your hands return to after every key, so the reaches to other rows always start and end from the same place.
the bumps on f and j
Run your fingertips along the middle row and you will feel a small ridge on the f and j keys. They are there so you can place your hands correctly by touch, without looking down. Getting used to finding home by feel is the single habit that makes touch typing possible — once your index fingers know f and j, the rest of the keyboard is described relative to them.
reaching and returning
Every key off the home row is a reach: the finger that owns a column moves up or down to the key, presses it, and comes straight back to its home key. The return is as important as the reach — if your fingers wander, you lose the reference point and start hunting. Practicing slow, deliberate reaches-and-returns is what builds the map in your hands.
start with the home row itself
Before reaching anywhere, spend time typing words made only of home-row keys so the resting position becomes automatic. The first lesson does exactly this, and each following lesson adds two or three nearby keys, always returning to home.