Touch typing is typing without looking at the keyboard. The idea is to teach your fingers the location of each keys. The F and J keys have a raised bar or a dot allowing your finger to identify them. Once you have placed your two indexes on those keys, the other fingers are placed on the keys next to them.
In order to type fast you have to be careful about which finger to use to press a key. Take a look at the drawing below. Each color match a finger. For example the left index is light green and has to type only the light green keys.