1.
[ no passive ] to make sb begin doing sth :
What started her off on that crazy idea?
Don't say anything to her—you'll start her off again (= make her get angry) .
[+ -ing ]
Kevin started us all off laughing.
2.
to help sb begin doing sth :
My mother started me off on the piano when I was three.
[+ -ing ]
His father started him off farming.