WorkGuru assigns staff to the the production job's tasks, not the job as the task is what the staff will be recording their timesheets against.   This also allows you to manage the tasks to specific staff members so they can only see, or add timesheets to, the tasks and production jobs that are relevant to them.

By default, non-admin staff members can only see jobs and tasks they have been allocated to in their timesheet entry screens.  If a production job has a mix of allocated and non-allocated tasks (a task with no staff, the allocated staff member will not be able to see the non-allocated tasks.

If you have a simpler workflow where it is easier to allow all staff to see every tasks on every production job, you can allow this via the Can Add Timesheets To All Tasks permission assigned to the staff members permissions or role. (Administration -> Roles)

You can assign staff when creating or by editing an existing production job.    Expand the task and add your staff by searching their name in the Staff Allocation field.   You can add multiple staff to a task by repeating the search.  Repeat this process for all tasks on the production job.

You can also easily assign multiple staff to a task using teams.   Select the pre-defined team in the Staff Team dropdown.  You can add multiple teams to the task if required.

Save the production job when staff assignment is complete.   The job's Overview tab will then display which staff are applied to which tasks.

An alternate way of adding staff to a production job if the same staff/team is always working on the same tasks is to allocate the staff in a production job template.   When the template is assigned to the quote, project or production job, the staff allocation will apply with the template and can be modified by editing the task as required.