The great thing about praying to God is that He is more concerned with what is going on in your heart than that you say the exact right thing. When you pray for forgiveness, it is most important that you want to repent or do something about your sins you have committed. And when you pray for forgiveness you need to remember that God has taken care of all our sins in Jesus, and that because of him you can be forgiven.
That said, I find it helpful to name my sins, because it helps me to really reflect on them, and pray for God’s help not to do them again. But I also pray for forgiveness for the sins I don’t know I have committed, because sometimes sin makes us blind to the awful things we do.
So really, it’s a matter of preference. I think it is a helpful thing to list the sins and think about them, but there are by no means any rules.
I hope that’s helpful! Praying that your prayer life blossoms and continues.