Spending time with the deceased before the service commences is a personal choice of the family.
If you have arranged to spend time with your loved one (viewing) before the service commences, the funeral director will guide you on arrival to the viewing area.
They will have requested instructions from you beforehand, as to who is permitted to attend, and if curtains are available whether they are to be open or closed. They will also have advised you of the length of time allowed.
On the day, they will usually keep you informed of the amount of time remaining before the service commences.
If the coffin is open, you can place letters, cards or personal mementos with your loved one at this time. If you find this too difficult to do yourself, ask your funeral director for assistance.
It is a good idea to take your seat a few minutes before the service commences, to try to compose yourself.