It's a bit tricky because it doesn't follow the typical "-ed" pattern of most verbs.
Tense:
The past participle "begun" is used in several tenses:
* Present Perfect: "I have begun my homework."
* Past Perfect: "I had begun my homework before you arrived."
* Passive Voice: "The meeting was begun at 9:00 am."
Let me know if you have any more questions!