Users per seconds starts at the same time?

I checked documentation and couldn’t find information about how gatling starts users in terms of seconds.
I mean, if, for instance, i need to run 20 requests per seconds, is all 20 requests will be start at the same time (at the same milliseconds)? Or they will be split somehow during this second? Who is deciding this? And do I have any ability to change this behavior? I want to make them start not in the same milliseconds.

Thanks in advance,
Daria

This is explained in the documentation: http://gatling.io/docs/2.1.7/general/simulation_setup.html
And if it’s still unclear, you can have a look at this video: http://technology-ebay.de/talks/2015-08-20_Load_Testing_at_mobile_de/

Video makes it clear!
Thank you so much!