“The eleven disciples.” The “eleven disciples” are the apostles minus Judas, who has committed suicide (Matt. 27:5). In Greek, the sentence has a de, which is usually a break or a change of subject. It seemed the best way to represent that break here was simply to start the new sentence without any connective particle in English.
“went to Galilee.” The “eleven disciples” now travel to Galilee. There is a long time break between Matthew 28:9-10, when Jesus met with the women and told them to report to the apostles and tell them to go to Galilee, and Matt. 28:16 when the Eleven actually go to Galilee. It would have been ten days or more.
Jesus had met the women on Resurrection Sunday, the 18th of Nisan and spoken with them about the disciples going to Galilee. But they were still in Jerusalem on Sunday the 25th of Nisan when he appeared to them a second time behind closed doors. Even if the disciples left that day for Galilee, it was usually a trip of three days.
Then between the first half and second half of Matthew 28:16 there is another time break. After the Apostles went to Galilee, Jesus met them on the Sea of Galilee, which is the third time he appeared to all of them together (John 21:14). Then, sometime after that meeting, Jesus met with the Apostles and a large group of disciples on a mountain (Matt. 28:16b).