In general the HTS would need to be connected directly to the source of the picture displayed on your monitor. PC, console, media box etc would connect to the HTs.
You will need to tell us what inputs and output are available on the monitor and the theater system. It might be or might not? No way to answer with the limited info you have provided.
In general the HTS would need to be connected directly to the source of the picture displayed on your monitor. PC, console, media box etc would connect to the HTs.