How is the rainforest damaged by people and industries?

There are many different causes of deforestation. One of the earliest problems to affect rainforests was "slash and burn" agriculture, in which farmers would cut down trees, burn them so that the ashes would fertilize the soil, and then farm the cleared land. There are two problems with this. The first is the initial destruction, and the second is that rain forest soils tend to be nutrient-poor, and thus the cleared land is only productive for a few years—then farmers repeat the process with new areas of forest.
In Malaysia and Indonesia, large companies are cutting down massive areas of rainforest to create vast plantations for cultivation of palms for palm oil. This is one of the major causes of deforestation in the world. Next, logging— especially of the illegal variety—contributes to deforestation.
Global climate change and population growth both have significant negative effects on forests as well.
https://www.nationalgeographic.com/environment/global-warming/deforestation/