Set up the team first
Only organization owners can invite teammates. Open Employer Settings -> Team to add people to the organization.
The Team tab is where owners invite teammates and review organization membership.
Share a job
Open the job and click Share in the job header.
Use Share from the job header when a teammate needs access to one job.

The Share project modal lists existing teammates who can be given access to the job.
Share a folder
Open the folder detail page and use Share from the folder header. Everyone added to a folder share inherits access to the jobs inside that folder.
Use the folder Share button when access should apply to the whole folder.

The Share folder modal shows how many jobs inherit the folder share.
Review project access
Use Job Settings -> Project access when you need a more detailed access review.
Project access in Job Settings shows the full access list for a standalone job.