A good place to start would be here:
http://support.sas.com/documentation/cdl/en/bidsag/65687/PDF/default/bidsag.pdf
There are plently of other useful documents in the same area as this that would be useful - don't hesitate to explore further.
I would recommend you pre-assign all library definitions when you create them in SAS Management Console so they are available to all SAS users automatically regardless of whether they use EG tasks, SAS code etc.
And if you pre-assign then setting the DEFER = YES option is also a good idea to avoid connecting to all external databases everytime you connect to your SAS server.
As best practice, you should also assign all of your permanent SAS libaries in SMC.
Happy administrating!