The answer is:
Populist movement sought to establish silver as an additional basis for currency, to increase prices so that farmers would have more profits.
Populist movement sought to reduce power of big banks and companies which had begun to control.
At that time, big businesses coluded together to only provide farmers with small price for their agricultural products before selling it to the consumers with a way larger margin.
This created an economic crisis among the farmers. Because of this, populist movement was created. This movement initially created to rise the agricultural product that provide economic help for farmers. Overtime, the movement also brought supports from workers in various field.