Before to apply you need your manager to approve that you are going to apply for other position.
Once is approved, you can apply up to 3 internal positions.
Positions can be only ant the same level that you are or one more level. You need at least 2 years in your level to apply for a next level.
Once submited, HR will review your CV, preform a background, and confirm with your manager that you have the approval to apply before to send the CV to the hiren manager.
If your CV is passed to the hiren manager it can take up to 2 months to get and interview or you can get a notification that the position has been close.
After this stages, depending of the role you will get a techncial test interview with 2 senior tech and 2 managers interviews.
After all this interviews you can get an offer or just a notification that you do not fill the requirments for the position