How Many Times
How Often
adverb, noun
How many occurences is just another way of asking how many times.
This word is more literary and formal than 何回 or 何度.
The reading is a combination of kun'yomi and on'yomi readings. That being said, both readings for both kanji are the readings you learned with the kanji so you should be able to read this.
彼は、幾度失敗しても、諦めなかった。
Even though he failed many times, he didn’t give up.