Service Templates are used to define the services your business provides. They contain details like pricing, description and contain the fields the user needs to fill out in order to request one.
A Service Instance represents a running service. The customer will be able to see the status, approve any charges, and pay for the services they request by viewing their instances.
A role is essentially just a container for permissions. Users are assigned roles.
Permissions make up roles and different parts of ServiceBot require different permissions in order to access them.
Funds represent your funding source (credit card). In order to request a service that costs money you need to have a valid funding source in your account.
Service Categories are groupings for Service Templates.
System options are site wide properties that affect things like branding, colors, and settings like registration being enabled/disabled.
Email templates detail the different emails that get sent out to users on certain events such as service instance creation or cancellations.