How did Jesus disciples know it was Jesus after he died?

Answer 1

Yes. Various references from the gospels, Acts and the epistles give various accounts which need not be seen as "conflicting," only different. None exclude the veracity of the others.

Matthew 28:16, 17 - Then the eleven disciples went away into Galilee, to the mountain which Jesus had appointed for them. When they saw Him, they worshiped Him; but some doubted.

Mark 16:12-14 - After that, He appeared in another form to two of them as they walked and went into the country. And they went and told it to the rest, but they did not believe them either. Later He appeared to the eleven as they sat at the table; and He rebuked their unbelief and hardness of heart, because they did not believe those who had seen Him after He had risen.

See also Luke 24:15-45, John 20:19-21:25, Acts 1:1-9 and 1 Corinthians 15:3-8.

[Quotes from NKJV]

Answer 2

Jesus appears to two of his disciples who are walking along the road to the village of Emmaus. Jesus walks and talks with them, but they don't recognize him because he doesn't have the same fleshly body that he had before. It is not until Jesus has a meal with them and says a prayer that they recognize him.

For 40 days Jesus appears in different bodies of flesh to show his disciples that he is alive. Then he leaves the earth and goes back to his Father in heaven.