I am really glad to read that you have a task, namely "to create a UBE to delete Work Center Messages". No problem at all.
Do you have any question, any problem with your task? If yes then please, share with us.
On the other hand, my practice is generally the following when I get something like task:
* I look for an original OW application/batch/business function which does something like I want to do
* Check-out it and open it with the appropriate designer tool
* Examine the logic and try to figure out how does it do
* I apply my new knowledge in my object(s) (APPL/UBE/BSFN/etc.)
Should I advise my method to you?
Hopefully somebody will give you a more exact and complete solution.
P.S.: Believe me, my mentioned method worked many times for me to resolve new task on new scope.