This is an app for beginners of Japanese to learn the first 440 Kanji. There are flash cards for the basic English meaning, the On and Kun Japanese readings, plus flash cards for about 1500 common words which use only these kanji.
Get a card right and it will be taken out of the drill. Get it wrong and it will be shuffled back in until you do get it right.
The key to learning kanji is regular review.
Every moment that you have a chance, take out your phone and do a practise drill.
Practise every day and watch your kanji grow.