dive into (something)
1. Literally, to jump or leap into something, often a pool. I was so hot after my run that I dove into the pool as soon as I got home.
2. To start a task enthusiastically, perhaps without much forethought. Because we just dove into fixing up our house, every room is under construction at the same time.
3. To begin eating something enthusiastically. Each kid dove into his slice of cake as soon as it was set before him.