You can find your local county court via the Court & Tribunal Finder. If you end up going to court, it is not guaranteed that you will be sent to your nearest court.
Court sitting hours are 10:30am-4:30pm; sitting hours mean literally when the judge sits to hear cases, so yours could be at any time during those hours and could be a very short hearing or a long one depending on the complexity of the case.
County Courts are open longer than the judges’ sitting hours as preparations need to be made in the morning before the court day, and then the building needs to be closed down at the end of the day. The court estate (the name they use to refer to all court buildings in England & Wales) has adapted to combat Coronavirus, and has measures in place so that the court can still continue to function.
You can read about the measures they have taken here: https://www.gov.uk/guidance/coronavirus-covid-19-courts-and-tribunals-planning-and-preparation
They are likely to change with the developing situation so you should check with the court beforehand whether you require a mask or any other safety precautions to attend court.
Many court buildings deal with all sorts of cases under one roof, but the county court only ever deals with minor civil (i.e., non-criminal) matters so it should be fairly straightforward to get to where you need to be. If you are stuck, ask the court staff to help you. You may want to bring water and some food if you are going to be there for a while, some courts have canteens but others do not. However, you cannot eat or drink in the courtroom.
You should arrive at court promptly for your hearing, and it is best to plan to arrive a little early just in case.