[SPANISH]
Quiero ser un guardia de seguridad y luchar contra el crimen porque mi padre es un guardia de seguridad y quiero ayudar a la gente.
[ENGLISH]
I want to be a security guard and fight crime because my father is a security guard and I want to help people.
"Quiero ser un guardia de seguridad" means that the person talking wants to be a security guard. Instead of saying "Quiero ser un seguridad guardia" you say that you want to be a guard of security.
"Luchar contra el crimen porque mi padre es un guardia se seguridad" is quite a obvious one, the person wants to fight crime and criminals because his/her is a security guard, but instead of saying that you want to fight crime, you say you want to fight against crime: "Quiero luchar contra el crimen".
In the end the of the sentence, the person talking about it says that he/she wants to help people ( " y quiero ayudar la gente " ). Instead of saying " y quiero ayudar gente " ( " and I want to help people " ) you say " y quiero ayudar la gente " (" I want to help the people.
if my answer didn't explain the problem well, I hope you find someone that does it better :).