Will I receive a letter to go before a judge to hear my case before they approve them to start taking money out of my pay check.

I think the best advice I can give you is to contact an attorney but do it sooner than later, if there is a court date attached to this garnishment and you miss it, well then its too late.

You will get served notice of for the hearing of the judgement. Once they have a judgement normally there is no future notice.
A few states ( such as TN) has state laws that require a notice, but often this rule is not followed if the company doing the collection is out of state.

To do the garnishment they have to get a judgement,