First of all you need to understand capitalism, so you know why these bad things are happening and why it can't be fixed within capitalism.
It takes 2 things to create a product, the means of production (factories, land, natural resources, etc.) and labour. This divides the population into two classes of people: the ruling class and the working class. The ruling class owns the means of production and the working class don't, this ownership is protected by law. Thus, the working class must sell their labour to the ruling class in order to survive. But the ruling class would only hire members of the working class if it would increase their profits, otherwise why bother? So, the wage that a worker is payed must necessarily be less than the value they produce. But, they can't do anything about it, since the boss owns the means of production, they decide completely how much the worker is paid, what hours they work, what they wear when they are at work, whether or not they get fired once their job is automated, etc. and if the worker puts up a fuss, the boss can easily fire them and replace them with a worker who is more docile.
This problem is compounded with the second feature of capitalism: the market. In order to increase their profits, the ruling class has a few options: they can increase their market share, through advertising or they can pay their workers less, replace workers with automated robots, move factories overseas where workers can be paid a lot less and can be made to work for longer hours, pay politicians to relax laws/remove regulations, pay politicians to start wars to take natural resources, etc. Now, the main point is that, since the ruling classes are competing on a market with each other, if one of them decides not to do these things, another one may, and in doing so will push the other out of the market.
Thus, the interests of the ruling class are to maximise profits, which is at odds with the interests of the working class, but the ruling class has all the power. So what next, right? Well, socialists advocate for "workers control of the means of production", which can mean a lot of different things to a lot of different people, so look around for different solutions.
Hope this helped!