Hi!

If you mean , how to revise total syllabus in 20 Days , then follow the following form the Day 1!

Prepare a List or Schedule that what you have to study and what your Syllabus is . And decide your timing accordingly when you can Study and how you will cover up full syllabus in 20 days, break down your syllabus accordingly.

Be consistent,  and study regularly.

Best of Luck!