If you say “I’m off to . . .” and follwed by a place or verb, it means you’re going to that place or do something.
– I’m off to Bali this weekend.
Meaning: I’m going to Bali this weekend.
– I’m off to bed.
Meaning: I’m going to sleep.
– We’re off to see a movie tonight.
Meaning: We’re going to watch a movie tonight.