In the Finalists phase the field is narrowed to allow you to work with your top five designers, which can be changed at anytime. Limiting submissions to the Finalists ensures more personalized attention and dedicated service. A Designer is much more likely to go farther with you if they are only competing with four others, instead of dozens and dozens.
The Finalists phase will last for two days, and once complete will move to the Selection phase.
If you have been ranking during the Open phase, you will likely already have your Finalists when the phase transitions.
You will see in your ranking area an indication of which designers are your Finalists.