The Defense's Witness(es)
Now you get to present your case. You may testify, but you do not have to. Indeed, if the prosecution has failed to prove their case, you may wish to simply move for a dismissal. You may also call any other witnesses you have present.
Any witness (including you) should stay on point. State the facts honestly, and do the best to make points supporting your case.
If you call any witnesses, you will get to question them. Do your best to help them stay on point, state the facts honestly, and make points supporting your case.
Staying on point will help you establish credibility with the judge. Stating the facts honestly will help when you (and your witness(es)) are cross examined.