How To Be A Delegate
The Texas Democratic Party has a whole page of information about this
year's National Convention. The essentials are is in this four-page pdf.
Friendly tip: when seeking election as a delegate, you may be asked if you are a Sustaining Member of the Dallas County Democratic Party (you can pay or sign up for monthly payments online at this page), and also whether you are a supporter of the Texas Democratic Party as a Majority Builder ($10 or more a month, which you can sign up for online at this page). Contributing to both the local and state party like this is not required to be a delegate, but it just may sway some voters at the Convention.