Gatling - ConstantUsersPerSec

In latest version of gatling, ConstantUsersPerSec(1) during (60 seconds)

  1. maintain overall 1 user for the period of 60 seconds?
  2. or it will increase 1 user per second and at the end of 60th second, the overall user is 60?

Thanks for your time.

None of those.
Will start a new user every second for 60 seconds. How long the users live and how many at the same time depend entirely on your scenario.