As opposed to only item storage, Refined Storage is able to store fluids as well. This is done in the entirely same way as item storages.
All the things you can do to manipulate items (with exporters or importers) you can do with fluids as well.
The same way as you connect item storages, you can connect fluid storages as well:
Any fluid storage disk in a Disk Drive
Any fluid storage block
External Storage in fluid mode
Use a Fluid Grid.
Any block that would manipulate items can manipulate fluids as well by simply putting the block in fluid mode.
There is one exception to this: the Interface has no fluid mode. Use a Fluid Interface instead.