Negotiate with the plaintiff's lawyer to see if you can either make arrangements to pay it off by a particular date, or to pay it off in installments. If you don't answer the summons by the deadline, and have no agreement for an extension from the plaintiff, you can expect a default judgment to be entered against you.

The most common means of collection are garnishment of wages and bank accounts, although it is possible to pursue other assets as well (subject to a state's exemptions on garnishment and execution).