The Insertionsort Algorithm
p...and inserting it in the place that keeps the sorted side arranged from small to large.
[0]       [1]        [2]       [3]        [4]       [5] 
Sorted side
Unsorted side
...and insert this element at the correct spot of the sorted side.

In this example, the front element of the unsorted side is 20. So the 20 must be inserted before the number 45 which is already in the sorted side.