How was I saved?

You should ask this question in future tense; Jesus says:

Matt.24
[13] But he who endures to the end will be saved.

So, if anyone says to you, "I was saved." you know it is not true.  The Lord never violates our free will, and anyone may decide at any time to fall away.  I trusted our Lord in 1947 and my trust has never wavered, but how do I know that some new trial will not crush my faith? 

Will I be saved?  Yes, if I endure; that is my earnest hope and expectation. I gain confidence every day and year; I do not doubt and it is wonderful to know that, every day, the choice is mine to follow him or not because his Truth has made me free.

But you ask "How." Jesus again provides our answer:

John.5
[24] Truly, truly, I say to you, he who hears my word and believes him who sent me, has eternal life; he does not come into judgment, but has passed from death to life.

In speaking of my word, he clearly means the words that he, Jesus of Nazareth, uttered in the world and that are recorded in the gospels:

That's the words we must hear and believe to receive salvation (eternal life).  Believing something about Jesus doesn't do the job.  We must actually believe him and continue believing.

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You also ask, "Where did I get my interpretation of the Word of God?"

Again, we must go to Jesus:

John.5
[39] You search the scriptures, because you think that in them you have eternal life; and it is they that bear witness to me;
[40] yet you refuse to come to me that you may have life.

Everything comes from going to Jesus and listening as he speaks -- and from believing him.

John.10
[27] My sheep hear my voice, and I know them, and they follow me;

I receive my interpretation of scripture from Jesus.  You can too but only if you will listen to him and believe.

Peace to you,