"Third" here is a ordinal number. This refers to nine o'clock in the morning. AT: "nine o'clock in the morning" (See: [[rc://en/ta/man/translate/translate-ordinal]])
The soldiers attached this sign to the cross above Jesus. AT: "They attached to the cross above Jesus' head a sign on which" (See: [[rc://en/ta/man/translate/figs-explicit]])
This can be written more clearly. AT: "one on a cross on the right side of him and one on a cross on the left side of him" (See: [[rc://en/ta/man/translate/figs-explicit]])