2 Google's Telephonic interviews which focus on basic problem solving and data structures
2-4 Google's Coding Onsite interviews which involve whiteboarding solutions to slightly harder data structures / algorithmic problems. The lesser experienced you are, the more number of coding onsite interview rounds for you.
0-2 System Design Onsite interviews which involve coming up with high level design architectures for real life products. The more experienced you are, the more number of these interviews you might face.
Where to Prepare
Coding rounds: Material in the programming section of InterviewBit is pretty comprehensive. For your reference, the section below has some of the questions which are frequently asked in Google's Interview. Make sure to try and solve most of them.