Step 1) Verify Brand Name & Download Application
First, verify that the name you want to register/file isn't already taken or too similar to another name by leveraging the Business Filings Search page through the Sec. of State's website. If you think there may be trademark issues, use the TESS System through the U.S. Patent Office to check.
In Louisiana, you can download the Application to Register Trade Name, Trade Mark or Service Mark form from the state’s official website as well for convenience.
Now would be the perfect time to make sure there’s a web domain available for your DBA.
Step 2) Correctly Fill In Form
If you don't have a lawyer in your pocket and you aren't working with a DBA filing service, be sure to read and understand all three pages of the form before filling anything in.
Read the instructions carefully, double/triple check your answers and use as many of the numerous resources out there if you have any questions or are feeling unsure.
Step 3) Notarize & Submit Your Form
When you're ready make the document official, have it notarized by an authorized individual. After that it's just a matter of filing with the Louisiana Secretary of State (check the form for specifics).
Once you get confirmation, that's all there is to it.