SCCM: Add a client to the sccm console

I have installed a SCCM system. My problem now is that I don’t know how to integrate clients that are on the same network like the SCCM. I have already created a location in the SCCM-Console and i have to integrate application software into the SCCM. The Testclient already has a Windows 7 installed. My question: How do I connect a client with the SCCM?