I would suggest walking through the tutorial in the BV Help file. That will at least get you started and show how to set up the basics.
After that, open up your Data Foundation. Create a filter and edit the rights. Apply the rights to a group or user. Whenever a user from that group logs in and view the report, that filter will be applied. It even works if that users is creating a report off that view. Since they have to log into CE to get access to the Business View (it is stored in the repository), the filter will apply.
Also, if someone with full access runs the report in CE and creates am instance, if one of those users logs in, and views that report, their filter gets applied.
I hope this explains it enough. Let me know if I need to add more detail.
~Brian