I posted four beginner YouTube videos in another thread, Is there a video series for terrible beginners? . The last two walk you through playing 9x9 against Igowin. I had lost my first four games against that app, but after watching those two videos, I won the next game. I don’t know whether Natsu Fuego is stronger than Igowin, but you still might pick up some pointers there.
I know what you mean about “easy.” Right now, I’m playing 13x13 against Fuego (Weak) with the Little Go app. The other settings are Strong and Extra Strong ( ! ). Since I am losing against the Weak setting, I will be watching this thread for other suggestions from more experienced players.