The tribes were the descendants of the 12 sons of Jacob whom God renamed Israel.
1 Chronicles 2:1 These are the sons of Israel; Reuben, Simeon, Levi, and Judah, Issachar, and Zebulun, 2 Dan, Joseph, and Benjamin, Naphtali, Gad, and Asher.
In Egypt, Jacob gave Joseph a double portion by taking Joseph’s sons Manasseh and Ephraim as his own
Genesis 48:5 And now thy two sons, Ephraim and Manasseh, which were born unto thee in the land of Egypt before I came unto thee into Egypt, are mine; as Reuben and Simeon, they shall be mine.
This made 13 tribes.
God took the tribe of Levi to be priests which meant that they received no inheritance of land in Canaan.
Deuteronomy 18:1 The priests the Levites, and all the tribe of Levi, shall have no part nor inheritance with Israel: they shall eat the offerings of the LORD made by fire, and his inheritance.
Joshua 13:14 Only unto the tribe of Levi he gave none inheritance; the sacrifices of the LORD God of Israel made by fire are their inheritance, as he said unto them.
Joshua 13:33 But unto the tribe of Levi Moses gave not any inheritance: the LORD God of Israel was their inheritance, as he said unto them.
This meant that for inheritance purposes the tribes of Israel numbered 12.
The tribe of Levi were given cities spread throughout the 12 tribes.
The 12 tribes were united as a kingdom under Saul, David and Solomon.
In the split after Solomon’s death the kingdom was divided into two.
The southern kingdom called Judah consisted of Judah and Benjamin.
The northern kingdom called Israel was made up of the other 10 tribes.
The tribe of Levi remained scattered through the 12 tribes.
When Christ returns the mortal descendants of the tribes will be restored to the land of Israel as described in Ezekiel 48.
Christ will rule the earth from the throne of David.
Luke 1:32 He shall be great, and shall be called the Son of the Highest: and the Lord God shall give unto him the throne of his father David: 33 And he shall reign over the house of Jacob for ever; and of his kingdom there shall be no end.
The twelve apostles will judge the 12 tribes of Israel.
Matthew 19:28 And Jesus said unto them, Verily I say unto you, That ye which have followed me, in the regeneration when the Son of man shall sit in the throne of his glory, ye also shall sit upon twelve thrones, judging the twelve tribes of Israel.
I hope you find this helpful.