Although roamers typically create their own jobs, an admin or crew boss can create all of the jobs for a roamer for a given day via the admin site.
First, create a job as you normally would, but find and click the "Create several jobs at once..." button to the right of the screen.
This will open a new menu, where multiple jobs can be created at once.
Here, there are a multitude of options to make use of:
Date: The date that these jobs will take place.
Employee: The Roamer that will work at these jobs.
Jobs: A mutable list of jobs to create. Each job will require a Ranch and a Task as per usual, but can also be given a Block and Variety. They will also each require a clock-in and clock-out time.
Hourly Pay: The base pay of these jobs, if needed (can be left at 0.00 if the employee's custom wage or minimum wage is being used).
Finalized? Whether or not these jobs should be created in finalized form, for convenience.
Bulk creating jobs for roamers this way means that the roamer won't need to clock-in or out of jobs at all. This does it all for them (with set start & end times)!