You will have a Default group to begin with that all team members will be assigned to. All team members will then follow the rules you setup within this default group. If you want some workers to follow a different set of rules, you would press "+ New Rule Group" in the top right.

This will create an Untitled rule group for you to use. You can assign a name to it at the top. This name is just for internal reference. The name can be changed at any time using the pencil icon next to the name.

You can then assign the team members you'd like to be in this group. You can type in their name, or hit the downward arrow on the right side to open up a list of your team members.

You can also see/adjust the group someone is in from their profile. You can go to Team members -> Open their profile -> Settings.

Note: The time clock rounding is a global setting and unable to be adjusted for others groups. All team members will follow the time clock rounding of the Default group.

See more about the time clock rules here: Time Clock Rules & Groups