home theater connections

hi, i am new to this group and new to the whole concept of posting to a group.this is my last resort for a fairly simple solution, i am sure.

i just bought a home theater projector and i have a sony 5-1 channel home theater.the only cable that i have are the white,yellow and red.i dont know if the cables should go into audio out of the home theater or in?? the only slots that the projector has are

1. Service Connector
2. RS232 Input Connector
3. VGA Input Connector (PC Analog signal/SCART RGB/ HDTV/Component Video)
4. S-Video Input Connector
5. Composite Video Input Connector
6. Audio Output Connector
7. Optical Audio Output Connector
8. Kensington MicrosaverTM Lock Port

1. Power Socket

the home theater has regular audio in,out and other typical connections.

please suggest what to do.i cant believe i amnot able to do it.so dumb.

thanx in advance.