Mattias chosen to replace Judas

Acts 1:12-26
Mattias chosen to replace Judas.
On the mountain of Olives, a Sabbath day's walk from the city.
Criteria of apostle. Peter said.
Therefore it is necessary to choose one of the men who have been with us the whole time the Lord Jesus was living among us. beginning from John’s baptism to the time when Jesus was taken up from us. For one of these must become a witness with us of his resurrection.
So they nominated two men: Joseph called Barabbas (also known as Justus) and Matthias. Then they prayed, “Lord, you know everyone’s heart. Show us which of these two you have chosen  to take over this apostolic ministry, which Judas left to go where he belongs.”  Then they cast lots, and the lot fell to Matthias
As far as we know, this is the last tome the apostles use the time-honored method of casting lots. It is not just a 'lucky dip; - the decision is made after much prayer. The 12 apostles parallel the 12 tribes of Israel, so the number must be made up. The twelfth man must have been with Chris throughout his earthly ministry, and have seen him after the resurrection.
Why?
For there are 12 tribes of Israel, so they chose apostles be 12 for the Judas is dead.
The criteria of apostle is run through 1)meet the conditions as Peter said, chose two,2)then prayer, and 3)cast lots.
How?
To be a church leader like Peter, made criteria, choose persons, prayer and cast lots. God is our Lord, we make decision through Holy Spirit.