Hello, and thank you for your help in advance

Hello, and thank you for your help in advance. I have a 1995 Chevy Lumina ls 3100 series engine. I recently replaced head gaskets and had heads resurfaced, cleaned, pressure checked and valve job performed. I have put engine back together completely and car seems to be ruining well but I have not ran it long as I have a concern if it overheating, my question is how can I check to make sure cooling system is working properly before I run it to long and it overheats with out me catching it before something major goes wrong again. So I just need to know steps in making sure everything on cooling side us working properly. If you have any questions that will help you better answer my Queston please ask and I will respond asap. Again thank you for your time and help. Thank you, bj w.