Orthodox liturgy on Sundays is rich in prayers, tradition and deep mystical meaning.
It usually starts directly after the Matins and for people not familiar with it will find it difficult to understand when one ends and the other starts.
A normal sunday liturgy will last almost two hours.
Liturgy can only be served in the morning and if there is someone receiving the Holy Gifts for communion.
Non orthodox are not allowed to receive holy communion in an orthodox church. As a form of respect, non orthodox should stay in the narthex or at the back of the nave if the church doesn't have a narthex. Unless having permission from the priest to be elsewhere.
The service will be full of rituals and prayers to feel the presence of God.
In orthodox churches the faithful will stand for much of the time and will often make the sign of the cross.
At the end of the service the priest will distribute the Antidoron, which means instead of the gift. This piece of bread has been blessed but has not been used during the preparation of the Holy Gifts. everyone can get a piece of it. This is a blessed piece of bread that has been blessed by god for the people of God.