The tithe is 10% of your possessions. Abram (later Abraham) gave a tithe of all he had to Melchizedek after Melchizedek blessed him. “Tithe” literally means “tenth.”

And Melchizedek king of Salem brought forth bread and wine: and he was the priest of the most high God. And he blessed him, and said, Blessed be Abram of the most high God, possessor of heaven and earth: And blessed be the most high God, which hath delivered thine enemies into thy hand. And he gave him tithes of all. - Genesis 14:18-20

Nothing has changed. If you earn money, then you tithe money. If you grow crops or raise animals then you tithe your crops or animals. Or sell them and tithe the income. Some may ask if you are to tithe before or after taxes. Start with 10% of every deposit of income into your bank account and see how you feel from there.

The tithe is distributed once per year. Until then, set it aside. I recommend using an investment app such as Webull or Robinhood so that you can easily transfer the tithe out of your bank account as soon as your income is put into your checking account. It can then be invested to grow for the year until it is time to cash out.

10% of the tithe, the heave offering, goes to the Levites.

Thus speak unto the Levites, and say unto them, When ye take of the children of Israel the tithes which I have given you from them for your inheritance, then ye shall offer up an heave offering of it for the Lord, even a tenth part of the tithe. - Numbers 18:26

The Levites are the people who run the church. They had no inheritance and so they were paid the best portion of the tithe. If 1000 chickens were born and raised in a year, the tithe would be 100 chickens, and the Levites would get the 10 best chickens to do as they pleased with.

And ye shall eat it in every place, ye and your households: for it is your reward for your service in the tabernacle of the congregation. - Numbers 18:31

No quarter is better than another quarter, so if you earn $50,000, you would tithe $5,000 and give the church leaders $500.

The other 90% goes to the storehouse. Your church has a storehouse, right?

Thou shalt truly tithe all the increase of thy seed, that the field bringeth forth year by year. And thou shalt eat before the Lord thy God, in the place which he shall choose to place his name there, the tithe of thy corn, of thy wine, and of thine oil, and the firstlings of thy herds and of thy flocks; that thou mayest learn to fear the Lord thy God always. And if the way be too long for thee, so that thou art not able to carry it; or if the place be too far from thee, which the Lord thy God shall choose to set his name there, when the Lord thy God hath blessed thee: Then shalt thou turn it into money, and bind up the money in thine hand, and shalt go unto the place which the Lord thy God shall choose: And thou shalt bestow that money for whatsoever thy soul lusteth after, for oxen, or for sheep, or for wine, or for strong drink, or for whatsoever thy soul desireth: and thou shalt eat there before the Lord thy God, and thou shalt rejoice, thou, and thine household, And the Levite that is within thy gates; thou shalt not forsake him; for he hath no part nor inheritance with thee. - Deuteronomy 14:22-27

You are to use a portion of the tithe to eat whatever you desire. What you determine the tithe year to be is your business. There is no declared “fiscal year” that you are required to abide by. Personally, I go from November 1st to October 31st the following year. Thanksgiving is then the tithe feast. And the holidays are a great time to look around for ways to serve with the money you have set aside.

At the end of three years thou shalt bring forth all the tithe of thine increase the same year, and shalt lay it up within thy gates: And the Levite, (because he hath no part nor inheritance with thee,) and the stranger, and the fatherless, and the widow, which are within thy gates, shall come, and shall eat and be satisfied; that the Lord thy God may bless thee in all the work of thine hand which thou doest. - Deuteronomy 14:28-29

The tithe is on a 7 year cycle. The first, second, fourth, and fifth years you feast outside the gates and give the remainder for the storehouse. The third and sixth years you feast with the Levites, strangers, fatherless, as widows inside the gates. And the remaining tithe goes to the store house.

The 7th year is a year of release and you do not tithe. It is up to you to keep track unless the church you attend has already established a 7 year tithing cycle. For myself, 2022 is the 4th year in the cycle. The calendar year is whatever year the feast falls on.