Need advice on how to apply for a job, how to apply for a job for people from poor rural backgrounds, and through what channels.

First of all, don't look down on yourself. Be confident.

Then write a resume according to your major or skill and your job search direction. You can put it on the recruitment platform and wait for HR to contact you. If you want to take the initiative, you can look at the company you want to go to. Generally speaking, there will be a recruitment section in official website. You can send your resume directly for consultation. You can also go to the local employment bureau to check, where there are generally recruitment information of enterprises, you can contact.

You must have self-confidence. Rural people are no worse than them, you won't, they are no better than you, and they may not be as hardworking as you. So keep trying.