"Why bother thinking today and stepping on the clear autumn?" poetic sentiment

When can this horse put on the golden halter and let me gallop freely in this late autumn? Li He desert sand as snow, Yanshan moon as a hook. Don't be a golden brain, go and step on the clear autumn. The whole poem means: at night, the endless desert is as white as snow, and the waning moon hangs on Yanshan Mountain. When can this horse put on the golden halter and let me gallop freely in this late autumn? The author of this poem expressed his disappointment, anxiety and sadness.