Provider personal settings
Some service settings can vary by provider instead of being fixed for the whole service. The plugin defines which settings can be delegated; admins decide, per service, which of them to delegate — see Personal service settings for that side of the workflow.
What a provider sees
Providers open the service and find its Personal settings: the service-wide settings and notifications are for administrators only. A delegated setting appears there for every provider, who sets their own value; the panel reminds them that "Your changes here only affect the service when provided by you". Each user can change only their own values: an administrator who is also a provider sets their own, not the other providers'.
Settings that were never delegated keep a single value shared by every provider. See the list of settings you can delegate. The Google Calendar settings appear only after the provider connects their own Google account.
Participate
Every provider also gets a Participate toggle per service, on by default. Turn it off to exclude that provider's availability from the service temporarily — for vacations, for example — without touching their underlying schedule. Turn it back on and the original availability applies again.
Timezone and Google account
A provider's Timezone (used for their own notifications) and, if allowed, their own Google Calendar connection are also personal — see Roles and the provider list and Connect a Google account.