I also suspect a troll, because poster has not replied, and because she states everybody sang and seemed to know the songs by heart, that certainly does not sound like the average Catholic church, since everyone knows we can’t sing.
Perhaps we should just give the OP a chance? It’s only been around 2 hours since the post! The OP may have well arrived in the middle after the Gospel or something. Or might have gone to a rare Catholic parish.
I was just wandering if there is usually a Bible reading at Sunday morning Mass, I attended my first one, but there was no reading, and alot of things were sang and said that all the people seemed to know by heart, but I didn’t understand any of them. Just hoping someone could explain to me, thank you.
Your profile doesn’t state which denomination you are coming from, so I’m assuming that it does not follow a liturgical format.
The services of the Church have a liturgical format that consists of fixed parts and variable parts.
You can see the outline of the Mass with the text of the fixed parts here
Since a lot of the Mass is fixed, especially for the people’s parts, people usually know it by heart.
As regards the songs, in some places, they sing all or some parts the Mass. This is the ideal, actually, since the Mass is a solemn act of worship. So the priest may sing “The Lord be with you” and the common response which the people may sing back is “And also with you”. The following fixed parts (which you can find in the link above) are among the commonly sung parts at a Sunday Mass:
Lord have mercy
Glory to God in the highest
Holy, holy, holy
Memorial Acclamation
Lamb of God
The variable parts include Entrance songs, Offertory songs and Communion songs (and a lot of the time, a Closing song). The Church usually has verses from Scripture and psalms for most of these these parts, but I think in most places, they are replaced by other (hopefully suitable) hymns/songs.
The other variable parts include the Scripture Reading: an Old Testament Reading, a psalm, a New Testament Reading and the Gospel. These change with every Mass. They are in a book called the Lectionery and you can see a schema of lectionary readings for different Masses
here
There are also 3 variable prayers that the priest prays that also change with each Mass- the Opening Prayer (or Collect), the Prayer over the Gifts (before the Eucharistic Prayer) and a Prayer after Communion just before the Mass ends.
I hope some of this is clearer than mud- if not, you can ask.