Operator Precedence is kind of like the PEMDAS anagram we use to understand our order of operations in math. However with programming there is a bit more going on as they describe a logical flow of operations.
What the MDN page describe is that the logical flow of operators can move in various directions however the precedence of an operator determines how soon it acts before others. Operators of a left to right flow be chained together on values.
1 + 2 + 3 * 4 / 10
or they can affect values on their left.
let a = 0;
a++;
a; // 1