People Manager rights are located in Tools -> System Configuration -> User Setup. Select the user you want to edit and click "Edit". Then, on the right hand side, there is a tab named "People Manager". Drop down the Region and Office and select a user. You can then edit the checkbox options for that selected user.
Here are definitions for each checkbox in People Manager:
Approvals - Grants rights to approve jobs for selected user, assuming you belong to the approval group and have rights to approve for that approval group.
Read-Only - Allows you to open the selected user's proposals, but not edit them. Selected user's jobs will only open as "Read-Only"
Bin Passing - Adds selected user as an option to pass bin manager to
Splits - Allows you to split commissions with selected user
Managed - marks you as the selected user's manager. Effects commissions.
Accounting Import - Grants rights for you to import jobs won by selected user to your accounting system
Commissions - Allows you to manage commissions for selected user. Also allows you to select them on the Commissions URG
Approval Emails - Sends you an email every time selected user submits a job for approval
Master Override - Job Sharing removes any shared user from the approval process. This means if I share a job with my sales manager, then my sales manager would not be allowed to approve my job anymore, because I shared with him. Master Override is used to override this rule.
Job Sharing - Allows user to right click a job and select "Share Manager"
Summary Report Email - When selected user wins a job, you will get an email copy of the summary report for the won job.