First, we must be able to read one-handed symbols. 1 is do2, re3, mi4, fa5, so6, la7, xi8, do and so on. If there is a bit on a number, it is one octave higher and the next bit is one octave lower. There are two points at the top that are two octaves high, and the next point is two octaves lower.
By analogy, if you have learned and mastered it, you can look at the two-handed notation. The rules of two-handed symbols are the same as those of one-handed symbols. The rules of the left hand and the right hand are exactly the same, both based on the central do.