Enable the Bulk Scheduling feature from your Workspace Settings (you may need to upgrade your Workspace). From the 3. Pooling Oversight UI & Tools Page, Find the "Scheduling" section, and Click on it to continue.
Once in Scheduling, you may configure Time slots by selecting "Set up a Test Schedule" to create new options for individuals to schedule.
Go through the wizard to setup an option:
You can also use the "Clone" feature to save yourself time and duplicate an existing time slot. You will want to edit the times and other details.
You may circulate the "Preview" link for your population to see. They can use this to schedule their times.