How does this Cura pause print work to switch out colors?

I have not tried the pause print function but I had a few questions before I did. If anyone uses this I would appreciate any input you have.

  1. Does anyone use this to switch out colors? If so how do you select a layer to pause at?

  2. How are you able to get the new filament extruded a bit so it comes out smoothly before you start again?

Thanks in advance.