Here we'll look at some key relationships between things you'll be able to configure in the administrator area (there are others, but these are the things you should do first).
Properties (AKA Businesses)
Firstly, let's look at businesses. Within the Jomres documentation, Businesses are synonymous with Properties (eg Hotels, villas) because Jomres' roots are as a hotel booking system.
Businesses can be defined as either MRPs or SRPs. If you're renting out the entire business (for example a villa or a yacht) then the business is an SRP. If you're renting out resources in that business (eg. rooms or boats or cars) then the business is defined as an MRP.
As a Site Administrator, you do not create businesses/hotels. This is done on the public facing pages, and is dealt with elsewhere in the documentation. At this point, all you are interested in is setting up an environment where businesses can be created on the system.
Property Types (AKA Business types)
A new business type creates a new subdir in /jomres/languages/ that reflects the business type's name. A new copy of the current language file is created in that directory. It is also a searchable option in the search modules/functionality.
Property Features (AKA Business features)
A property feature can be assigned a name, description and icon (you can upload icons via ftp to the /jomres/uploadedimages/pfeatures directory). A feature can be assigned to specific business types, in which case other business types will not see those features as options in the business details edit page. If your business is a hotel, for example, then you'll be able to use the existing features and icons that Jomres creates for you when it installs. If it does not, then you may need to create some yourself.
Room types (AKA Resource types)
Regardless of whether the business is an MRP or an SRP, when you use the booking functionality of the system, you're booking out resources. Resource types are defined by the Site Administrator, because it is possible to search on a resource type when looking for a business. When a resource type is created, it can be associated with one or more business types, and it can be configured to be visible to only MRPs or SRPs.
When a business manager configures their resources, they associate the resource with a resource type. Next, they'll create tariffs for those resource types. This gives us a many -> one -> many relationship, allowing us to have, for example, many rooms of type A, and one tariff that sets the prices for all resources of type A.
Don't panic if you don't understand all this, it will become clear in time.