Don’t bother pleading not guilty unless you have an attorney. It grants you (your attorney) time to negotiate with prosecutors to plead guilty to a lesser charge or similar. But an expired license is about the lowest charge you can get.

Traffic court is very routine. People get up, hear the charge, mostly plead guilty/no contest, hear their sentence (usually a fine, probably under $200 depending), and get pointed to where they can pay. You negotiate payment terms at the later office.

It will help to show how you’re going to address the original issue. Even just having an appointment at the DMV, which you can probably book online.