As a noun:
* His descent from the mountain was slow and treacherous. (meaning his journey down)
* The descent of the aircraft was smooth and uneventful. (meaning the landing)
* She traced her descent back to Irish immigrants who arrived in the 19th century. (meaning her ancestry)
* The descent into madness was slow and agonizing. (meaning a decline)
* The descent of the Roman Empire marked a significant turning point in history. (meaning the decline of something)
As a verb:
* The hikers descended the steep mountain trail with caution. (meaning they went down)
* The sun began to descend below the horizon, casting long shadows. (meaning to go down)
* As the temperature descended, the snow began to fall. (meaning to decrease)
* Her spirits descended as the news of her friend's illness reached her. (meaning to decline)
The meaning of "descent" can vary depending on the context, but these examples give you a good idea of how it's used.