The white cross on the map indicates where the entrance steps are to access the church.
Zoom in, using the + symbol at the bottom left of the first map, to see this in more detail.

There is parking within a short walking distance of the church; as well as further along St Margaret's Street, subject to a space being available. This is free parking for 2 hours during the day - as well as along nearby roads, Monday - Saturday; there is paid parking in the Station Carpark. Parking is free and unrestricted on Sundays.