There are multiple verses in the Bible regarding what we must do to be saved. There is obviously John 3:16, all of us should know that verse.
There is also Acts 16:30-31
Which was after Paul and Silas were singing hymns in prison, an earthquake happened shook the prison, the prison doors were open and chains were loosed, the prison keeper awoke from sleep and thought everyone had escaped and was about to kill himself, then Paul called out with a loud voice saying "Do yourself no harm for we are all here" the prison keeper called for a light ran in and fell down trembling before Paul and Silas.
Acts 16:30-31
"And he brought them out and said Sirs, what must I do to be saved?" So they said, "Believe on the Lord Jesus Christ, and you will be saved, you and your household."
John 5:24
"Most assuredly, I say to you, he who believes in Him who sent Me has everlasting life, and shall not come into judgement, but has passed from death into life."
Romans 10:9-10
"That if you confess with your mouth the Lord Jesus and believe in your heart that God has raised Him from the dead, you will be saved."
Notice what is the keyword in all the above verses? believe. So if you have made that choice and taken that step of Faith, I believe you are saved.
Ephesians 2:8-9
"For by grace you have been saved through faith, and that not of yourselves; it is the gift of God, not of works, lest anyone should boast."
I could keep on going about verses on being saved, but it will take all day, and maybe even then some. But if you take the word of God as it is and believe, you should be fine.
Also the see the 2nd half of 1 Corinthians 12:3
"Therefore I make known to you that no one speaking by the Spirit of God calls Jesus accursed, and no one can say that "Jesus is Lord " except by the Holy Spirit.
Throughout the Old Testament God is referred to as Lord very many times, "Lord our God" is used multiple times.
If you can say Jesus is Lord, you have absolutely nothing to worry about.
Also read 2 Corinthians 3:17
"Now the Lord is the Spirit, and where the Spirit of the Lord is, there is liberty."
The word "Trinity" is not in the Bible, it's just a term used to describe the Father, Son and Holy Spirit. Don't focus too much or stress out on holding a position on the trinity, when you read the Word of God, just take it as it is and if you do not understand, ask God to help you understand, even read through the verses a few times, read it slowly, there's no rush, and let the Holy Spirit do the rest in helping to bring you a greater understanding.
God Bless You.