Answer:
you can get infected with AIDS if you get in contact with body fluids of someone already infected.
For instance, if someone has AIDS and has injured themself and is bleeding, you try to help them, you have a tiny cut on your hand. the infected HIV blood will get in contact with the cut and the HIV virus might enter your body.
some common signs of having AIDS are, diarrhea, rapid weight loss, getting really tired without any reason and pneumonia.