I have had a judgement entered in against me. Now that has been done can they automatically seize my assets and bank accounts or is there further action required?

Well, they will have to file for a lien, or file for a garnishment or file for an attachment, but you will not be notified of those motions, those are allowed because of the judgement, so you will have no notice of these normally.
A few states have rules that you have to be notified prior to a wage garnishment ( they tell you the day before it happens often)