The Universal Secret Writing

In your case, the methodology consists of:

Enter practices and observe in animated frames how the letters are moving in red.
Read the practice boxes as if they were all blank.

Once you have understood

Read the letters in red from the beginning and understand the meaning.
Observe the title of each practice to understand which letters of the alphabet we have codified each practice.
Enter alphabet and study each letter of the subject of the course.
Go back to practices and understand the application of each letter in the practice boxes.
Repeat the same system with each table of the practices.

The letters with which we codify this practice are:

The letter A tells us that the code number will begin. for the highest number. In this case on 5 of the code 52.
The letter N tells us that the numerical jump of the numeric code will be from day to day. As well: 52 42 32 22 ...
The letter S tells us that each time we reach the last digit of the code, in this case on 2 of 52, we will return to start counting by number 2. Like this: 52 25 52 25 ...
The letter C tells us that the term of the words will be: linear in the sense of reading.