Application has to do with how a person is going to react or attempt to implement what they have learned from the scriptures.   How is what you've learned going to impact your life?   This question reveals the essence of application.

Of course  the most  common sense and direct  way to make application of God's word  is to  humbly obey  what we have been clearly  commanded to do, as James, the Lord's brother,  (and pastor or bishop of the Jerusalem Church) makes clear.

James 1:22-27

[22] But be ye doers of the word, and not hearers only, deceiving your own selves.
[23] For if any be a hearer of the word, and not a doer, he is like unto a man beholding his natural face in a glass:
[24] For he beholdeth himself, and goeth his way, and straightway forgetteth what manner of man he was.
[25] But whoso looketh into the perfect law of liberty, and continueth therein, he being not a forgetful hearer, but a doer of the work, this man shall be blessed in his deed.
[26] If any man among you seem to be religious, and bridleth not his tongue, but deceiveth his own heart, this man's religion is vain.
[27] Pure religion and undefiled before God and the Father is this, To visit the fatherless and widows in their affliction, and to keep himself unspotted from the world.

James 2:14-18

[14] What doth it profit, my brethren, though a man say he hath faith, and have not works? can faith save him?
[15] If a brother or sister be naked, and destitute of daily food,
[16] And one of you say unto them, Depart in peace, be ye warmed and filled; notwithstanding ye give them not those things which are needful to the body; what doth it profit?
[17] Even so faith, if it hath not works, is dead, being alone.
[18] Yea, a man may say, Thou hast faith, and I have works: shew me thy faith without thy works, and I will shew thee my faith by my works.

The Apostle John is the writer  of the fourth gospel  in our New Testament as well as three shorter letters that are included just prior to the Book of Jude and Revelation in the New Testament.

1 John 3:14-19

[14] We know that we have passed from death unto life, because we love the brethren. He that loveth not his brother abideth in death.
[15] Whosoever hateth his brother is a murderer: and ye know that no murderer hath eternal life abiding in him.
[16] Hereby perceive we the love of God, because he laid down his life for us: and we ought to lay down our lives for the brethren.
[17] But whoso hath this world's good, and seeth his brother have need, and shutteth up his bowels of compassion from him, how dwelleth the love of God in him?
[18] My little children, let us not love in word, neither in tongue; but in deed and in truth.
[19] And hereby we know that we are of the truth, and shall assure our hearts before him.

What's the purpose?

Why do we read and study and work to understand God's word? We do so because we want God's instruction so we can live in a way that is pleasing to him. We want wisdom for life we may be seeking peace or help with difficulties. The Berean Fellowship provides some great resources to assist with this! I strongly recommend that you take advantage of them.