the answer ,Christian, is that Phrasal Verbs take A LOT of practice. They are one of the hardest things about learning English. "Hear me up" does not exist. "Hear me out" means to listen to my entire story/what I have to say. Each phrasal verb is different and follows different rules. You must learn them and it takes time. If you want to take a class on Phrasal Verbs, message me to start practicing.

If you would say "help me out" it would be like persuading someone to help you out. That phrase is usually used when you fell down or slip so you're gonna ask somebody to 'help you out' or help you stand up. Even the phrase "try it out" is a way of suggesting something to someone for them to try it.

But when you say "help me out" or try it out" you are not suggesting going somewhere. So i don't quite understand.

Using "up" is usually for trying to persuade someone to do something. For example, "hear me up" is someone trying to get another's attention to listen to him/her. While using "out" usually is for suggesting on going somewhere. For example, "Let's eat out" which is someone persuading another to eat outside or eat at some other place.