“Don't expect to get a high-paying job right out of school.”
You are giving advice to a group of college students. These students seem to think that they will make a lot of money when they finish school, but you don't think that's a realistic expectation. You want to prepare them for the fact that they may have to take a job with a low salary at first. You advise this to them.
Don't expect to get a high-paying job right out of school.
To "expect" something is to think that it will happen. In the example above, "don't expect to get a high-paying job" means "don't think that you will get a high-paying job; realize that you might get a low-paying job"
When you use the phrase "expect to ___", the subject is both the person who's expecting, and the person who is doing the expected action. Take a look at this example:
I didn't expect to get a job offer so quickly.
In this sentence, the speaker ("I") is the person who didn't "expect" something, and also the person who got the job offer.
If the person who's expecting and the person who's doing the action are different, you use the structure "expect (someone) to (do something)":
I didn't expect him to get a job offer so quickly.
A job that you make a lot of money in is called a "high-paying job". The opposite is a "low-paying job".
This phrase describes the first year or so after finishing your schooling. It can mean after high school, after college, or even after law school, medical school, business school, or grad school - whatever type of school a person goes to before completing their education and getting a job.
This phrase is usually used to talk about your first job situation after graduating. You can use the word "school" like in the example above, or you can specify which type of school:
I started my first business right out of college.