Sodium percarbonate is useful as both a cleaner and a sanitizer.
For general cleaning use 30g per 10L of water, let it soak for 10min, and then rinse off. For line, cleaning use 30g per 3L of water.
Sodium percarbonate is a very effective cleaner and can penetrate and remove dry yeast, beer stone, etc. While it does degrade over time into safe components (oxygen, sodium carbonate, and water) it is not a no-rinse sanitizer. For that, you should use a phosphoric acid-based sanitiser at the correct dilution.
The active oxygen method of cleaning sodium percarbonate uses actively attacks any impurities on surfaces making it easy to simply rinse off with clean water after 10-20min depending on how caked on it is.