Remember that the earliest Christians were illiterate, with only 5-10% of the general population was able to read. So there were no hymnals, the Scriptures were copied by hand and cost around what someone might make in about a year. Definitely no Powerpoint presentations
In fact, my position is that of a Reader, a member of the minor clergy. In early Christianity, I would be entrusted with the scrolls or codex of the letters of the Apostles, while a Deacon or Priest would care for the Gospels. By the 5th century, Readers / Chanters, would be the equivalent of today's choir directors. They had to assemble the various services following a general guideline and teach others how to read as well as to sing. Its not like we could open up a hymnal to page 222 and expect a congregation to sing with a staff scale.
Regular patterns of worship were established from the Jewish temple and synagogue services. Early on, there were a lot of different liturgies, Byzantine, Syriac, Coptic, Roman, Gallic, Sarum, etc, depending on what part of the world you were in. However, these could be broken down into general families based on the various litanies or prayers said in the service. Overall though, they were fairly similar in construction. By about the 5th century, these had been developed into fewer sets.
In Orthodoxy, we have 3 liturgies:
St. John Chrysostom (5th century) which is the regular liturgy, about an hour long
St. Basil (4th century), used for special feast days and is a little longer than Chrysostom
St. James (3rd century), now only used on the feast day of St. James in October. It is the longest. I've only been to one and it was about 2 hours.
There is a Presanctified Liturgy used during Lent but it uses bread and wine sanctified on Sunday.
Even today a Jewish service is going to have a lot of similarities with a Christian liturgy (but without the Eucharist).
https://images.shulcloud.com/178/uploads/Documents/Shabbat Prayer Book Guide final.pdf
THE SATURDAY MORNING SERVICE
Shabbat morning services are made up of three
sections:
A. Shacharit
The first part of the morning service, on both Shabbat and during regular weekday morning services, includes:
1. Birchot HaShachar (morning blessings)
2. Pesukei D’zimrah (Verses of Praise)
3. The Shema (a declaration of the principal of our faith) and its blessings
4. The Amidah, reflecting the day’s theme of creation and rest, replacing the standard weekday format of the Amidah.
B. Torah
1. The Torah scroll is taken out of the Aron HaKodesh (Holy Ark).
2. It includes the reading of the weekly Parsha – the designated portion of the Torah
for that Shabbat.
3. The Haftorah is read – the designated reading of the Prophets for that Shabbat
that reflects the theme of the Parsha.
4. The new month is blessed (when applicable).
5. The Torah is returned to the Ark.
C. Mussaf:
1. An additional Amidah, which commemorates the added communal offerings for
festive days, like Shabbat, Yom Kippur, and Rosh Chodesh (New Month).
2. Concluding prayer