We learn to do by doing. We learn to give by giving. We will teach the people in the millennium the give way of life by leading them to give. There will be a great project during the millennium, to prepare for the white throne judgement.
The billions who will come up in the white throne judgement will need to be fed, clothed, and housed. They will need a multitude of supplies and equipment. There may even be more people raised up than the earth can feed with the farming produce that is produced during the white throne judgement period.
Growing needed food, manufacturing the clothing and other needed items, and building the housing that will be needed can be the work of the people during the millennium, and by so laboring, they will be learning the give way of life, not just by our instruction, but by putting the lesson into action.
"Let him who stole steal no longer, but rather let him labor, working with his hands what is good, that he may have something to give him who has need" (Ephesians 4:28).
It is similar to this time for the Church of God. We hear sermons about practicing the way of love and give, but we must also put it into practice to learn the lesson. God has given the Church a great work of love that goes beyond the Church itself - a labor of love of warning Israel about the tribulation to come if they do not repent of their sins and of preaching the gospel to the world as a witness. Likewise, in the millennium, we will preach to the people of the world the way of love and of give, but also, they will learn that way of life by putting it into practice - by contributing to the buildup of food, clothing, supplies, and physical needs of the billions who will come up in the white throne judgement. They will all be poor - there is no indication their possessions will be resurrected with them, just their bodies (Ezekiel chapter 37).
It will be a time similar to the time in the days of Joseph when grain was stored during the seven years of plenty, only this time, there will be a thousand years of plenty and we will be storing not only grain, but clothing as well, and we will be building houses and manufacturing furniture and anything else people will need (Genesis 41:33-49).
But the giving will not necessarily all be by compulsion as it was when Joseph ruled Egypt. Rather, we will teach the people to give willingly of their time, labor, and material possessions as their are able, and they will know that by contributing they are helping those who will come up in the white throne judgement, who will need all these things. When ancient Israel in the wilderness was asked to give for the tabernacle, they gave willingly (Exodus 25:1-9, 35:21-29, 36:2-7). "So let each one give as he purposes in his heart, not grudgingly or of necessity; for God loves a cheerful giver" (2 Corinthians 9:7).
We will be able to teach the people this way of life because that is the way we are learning ourselves when we give to the work of preaching the gospel to the world. We are not just helping our own Church of God group. We are extending ourselves outside of the group we are part of to serve the world - the millions we don't even personally know, people who are sinners and have not yet repented. Yet, just as God loved the world, which was sinning against Him, enough to sacrifice His Son for the world, likewise we are to love the world and give them what they need to repent, that is, the truth.
In the same manner, the people in the millennium will learn to help people they never met - those who come up in the white throne judgement - by contributing to the work of preparation for those who come up, to cloth them, to feed them, and to give them houses to live in. They will need those things immediately as soon as they are resurrected back to physical life, so we have to have everything ready on time.
So just as God has us learn the give way of live by giving to the work of preaching the gospel to the world and the Ezekiel warning to Israel, so also we will teach the people in the millennium the give way of life by leading them and teaching them to contribute what they are able to the physical preparations for the white throne judgement, cheerfully and with a willing heart.
That is an effective way to learn God's way of life and to build godly character.
Here are links to related chapters or sections in Preaching the Gospel:
The Feast of Tabernacles - the Millennial Rule of Christ, Chapter 2
The Last Great Day - the White Throne Judgment, Chapter 2
CHAPTER 3 - THE EZEKIEL WARNING
CHAPTER 4 - WHY PREACH THE GOSPEL? - A LESSON FROM THE HOLOCAUST
Should the Church Feed the Flock Only, Introduction, Chapter 5
Will Focusing Exclusively on Feeding the Flock Heal the Church?, Chapter 5