In order to calculate weight, center of gravity, power draw and space allocated, templates need to be created for each type of system that you are going to put into your data center. However, like most parts within openDCIM, this is an optional step - if you only want to utilize openDCIM to take a very basic inventory of your data center, you can simply not assign a template to anything.
The fac_Manuacturer table is very simple in that it only has two fields - ManufacturerID and Name. The ManufacturerID is an auto_increment field within MySQL that simply guarantees a unique ID for each Manufacturer.
We are currently working on the possibility of creating an opt-in synchronization function with the openDCIM.org website, so that templates can be shared with each other. There are a lot of logistics to work out, so there is no timeline on when this feature may be made available, if ever.