Barnes Commentary explains the word "know" as it applies here:

"Might know thee - The word “know” here, as in other places, expresses more than a mere speculative acquaintance with the character and perfections of God. “It includes all the impressions on the mind and life which a just view of God and of the Saviour is fitted to produce.” It includes, of course, love, reverence, obedience, honor, gratitude, supreme affection. “To know God as he is” is to know and regard him as a lawgiver, a sovereign, a parent, a friend. It is to yield the whole soul to him, and strive to obey his law." [Barnes Commentary - John 17:3]

All of that is very true. however, I would add one more word that was left out here, that makes the rest of it all possible. That word is "fellowship." To live in the abiding fellowship of the Father and the Son IS eternal life, IS salvation. [1 Yochanan/John 1]

When someone uses the word "salvation" in the Biblical sense they may actually be referring to one of two things, or both things. Yes, that can be confusing. Here are the two things "salvation" can be referring to:

1. The "salvation experience" is the experience of entering into fellowship with the Father and the Son. This involves repenting of one's sins and accepting Messiah as both Lord (meaning you will obey Him) and Savior (meaning you trust in Him and not yourself). You don't need more than the basics of understanding to do this. It has a lot more to do with your heart than with your head. Once you start down this road, you will keep learning and growing from there.

2. Being "saved" is an ongoing state of being in fellowship with the Father and the Son. This is what "walking out your salvation" really means. This must never stop, so long as one is sucking air. Here we learn that salvation isn't just an event that happens once. It is a state of being that must continue everyday. Your part is to "abide in Him" daily, and the rest of it will pretty much unfold. [Yochanan/John 15:1-15]

Once a person enters into salvation things happen fast. They receive the Holy Spirit within. Through the Holy Spirit and the Word, the eyes of their understanding are opened and the truth opens up more and more to them. As they walk in that truth, more truth will be revealed, and so on. This causes their life to change rapidly. Through this process the new child of God is led into ever greater fellowship with God, and learns how to perceive and to do His will. If the child of God puts on the brakes at any point, then the revelation will pretty much stop at that point, until they let go and start moving forward with Messiah again. The goal to which we press is transformation into the image of Messiah Himself, in us. Considering where we start from, and the perfection of character we are aiming for, it is not a big surprise that this can sometimes be a painful transformation. Painful, but also blessed, provided we do not give up before we reap eternal life. This is where grace comes in. Not grace to simply allow sin. No, but grace to help us overcome sin. Through His grace we can learn and be empowered to walk "just as He walked" in true fellowship with Him. [Eph 3:13-21, Yochanan/John 14:17,16:13, Acts 13:43, 14:26, Rom 5:21, Rom 6:1-13, 1 Yochanan/1 John 2:6]

Once saved, forget the complacent folly of "once saved always saved." Instead, take up the aggressive struggle to attain the Kingdom exemplified by the Apostle Paul:

However, what things were gain to me, these have I counted loss for Messiah. Yes most certainly, and I count all things to be loss for the excellency of the knowledge of Messiah Yeshua, my Lord, for whom I suffered the loss of all things, and count them nothing but refuse, that I may gain Messiah and be found in him, not having a righteousness of my own, that which is of nomos, but that which is through faith in Messiah, the righteousness which is from God by faith; that I may know him, and the power of his resurrection, and the fellowship of his sufferings, becoming conformed to his death; if by any means I may attain to the resurrection from the dead. Not that I have already obtained, or am already made perfect; but I press on, if it is so that I may take hold of that for which also I was taken hold of by Messiah Yeshua. Brothers, I don’t regard myself as yet having taken hold, but one thing I do. Forgetting the things which are behind, and stretching forward to the things which are before, I press on toward the goal for the prize of the high calling of God in Messiah Yeshua. Php 3:7-14