This program could have been recorded as a flow chart, or in English without all the indentation and other formatting, whatever format you use, it has captured the idea of what you do.
This is the algorithm - it's not a computer program yet, but it's a specific way of getting the result.
We were all doing this in our heads, but now we want to turn it into a computer program.
When writing a program, start with the problem you want to solve, then turn it into a general algorithm of what you want it to do so you have an idea of what will work.
Then we turn it into an actual program.
This is a good process for students, writing out a general algorithm first, before starting to program.