How did Zhang Qian go to the Western Regions?

In BC 138, in order to fight against Xiongnu, the increasingly powerful Western Han Dynasty sent Zhang Qian to the Western Regions to unite with other countries in the Western Regions to fight against Xiongnu. Zhang Qian, with a mission, led more than 100 people, led by a man of minority origin, Gan Fu, left Chang 'an and headed for the western regions via Hexi Corridor. During this period, she was captured by Xiongnu twice and married a Xiongnu woman under the pressure of Xiongnu. He overcame many difficulties with perseverance, walked through the Gobi desert, barren hills and wild forests, trekked thousands of miles, traveled to several countries in the western regions, and returned to Chang 'an in A.D. 13. When I arrived in Chang 'an, apart from his wife, it was only him and his father. Although Zhang Qian didn't accomplish the mission of unifying the countries in the Western Regions, he brought back a wealth of knowledge and insight about the Western Regions, which far exceeded his direct mission and had a far-reaching impact in the history of our country. Emperor Wu of the Han Dynasty was very satisfied with the achievements of this mission to the Western Regions. He named Zhang Qian as the emperor's counselor and raised him as the official residence. At that time, although the Western Han Dynasty won a certain victory in the war against Xiongnu, Emperor Wu's strategy towards Xiongnu remained unchanged, and he still needed to continue to seek allies in the Western Regions. Because of Zhang Qian's understanding of the Western Regions, he proposed to Emperor Wu of the Han Dynasty to contact Wu Sun of the Western Regions again. His suggestion was praised by Emperor Wu of the Han Dynasty and sent to the Western Regions again. In BC 1 19, Zhang Qian led more than 300 people to the Western Regions for the second time with priceless gold coins, silk and more than 10,000 cattle and sheep. And arrived at Sun Wu smoothly. In 65438 BC+065438 BC+05 BC, Zhang Qian returned to Chang 'an with Wu Sun's special envoy, and was named as a treasury, that is, a senior official in charge of receiving guests and ethnic affairs. After more than a year, he died in Chang 'an. During his stay in Wusun, Zhang Qian sent officials to western countries and arrived in Khotan (now Hotan, Xinjiang) south of Tianshan Mountain, and established friendly relations with western countries, the north and south of Tianshan Mountain and Central Asia in the Han Dynasty. During his mission to the Western Regions, Zhang Qian was deeply loved by ethnic minorities because of his ability of "being strong, tolerant and trusting, and being loved by barbarians". Later, the Western Han Dynasty successfully realized the intimacy with Wusun and formed an alliance and friendly relationship. When the Huns invaded Wusun, the Han Dynasty sent troops to cooperate with Wusun soldiers to defeat the Huns. Later, the Han Dynasty repeatedly joined forces with other countries in the Western Regions to fight back against the Xiongnu, and finally freed the people of all ethnic groups in the Western Regions from the slavery rule of the Xiongnu. Zhang Qian's two missions to the Western Regions enabled the Han Dynasty to establish friendly relations with countries in the Western Regions politically, especially through his close alliance with Wusun and others, which realized the strategy of Emperor Wu of Han Dynasty breaking the right arm of Xiongnu. After more than half a century's efforts, he finally established the Western Regions Duhu in Leo (now East of luntai county, Xinjiang) in 60 BC, and appointed Ji Zheng as the first Duhu. The capital of the Western Regions governs 36 countries in the Western Regions, and the Western Regions have since been incorporated into the territory of the Han Dynasty. Since then, the vast areas of Xinjiang (including the areas east and south of Lake Balkhash in Kazakhstan) have been placed under the jurisdiction of the Han Dynasty, which is not only a major event in the history of Xinjiang, but also a far-reaching event in the long history of China's unified multi-ethnic country. The history book says: "The order of the Han Dynasty's missions to the Western Regions began in Zhang Qian and ended in Ji Zheng." Explain the historical contribution of Zhang Qian. Zhang Qian made two missions to the Western Regions, exploring and opening up the famous communication channel between the East and the West-the Silk Road, which opened the prelude to the communication between the East and the West. Since then, handicrafts and agricultural products such as silk, sericulture, lacquerware, iron, smelting iron and well irrigation have been introduced to the Western Regions, while Korean envoys have introduced agricultural products such as grapes, alfalfa, pomegranate, walnuts (walnuts), flax (sesame), cucurbitaceae (cucumber), beans (broad beans), garlic (garlic), fur products and rare birds and animals from the Western Regions.