There's a whole sub-category on briefings in the Ed Depot tutes.
Also in Getting Started there is a simple tutorial mission which has one you can copy, and there are some Tools that can help you too.
For unit animations look at the Unofficial Command Reference Guide.
Sorry to hear you are having trouble accessing stuff, it's working ok for me. If you're having problems can you make a seperate post on the Editors Depot Feedback board with the exact details of what you tried to access and what went wrong? Thanks.