1)
How did Hashem teach to him?
1.
Radak: From my youth, You gave to me a heart to understand that everything is from You.
2.
Malbim: He does supernatural wonders.
2)
What is "v'Ad Henah"?
1.
Rashi: It is until today - what passed over me.
2.
Radak: From my youth until now, I constantly tell Your wonders.