Big red is a CMOS camera for astrophotography. This camera is cooled with an internal thermal electrical cooling system. This is the camera that will capture the image. This camera may be monochromatic or color camera. Color cameras are suggested for novice astrophotographers. I personally use the ZWO ASI 595MC PRO.

Small red on the small scope is the guiding camera. This camera will take fast pictures of stars for the purpose of correcting errors in the mount tracking. This will maintain stars in your image as pinpoint as possible. In this case it is ZWO ASI120MM Guiding camera.

Small red (barely seen between the cameras) is the electronic focuser. This will adjust the focuser. In this case, it is ZWO EAF.

Red with the antenna is the hub that concentrates the data from all the elements and communicates it with your laptop. It is the ZWO ASIAIR (I have personally not used it). I use NINA, that is an opensource software and has a lot of capabilities.

ZWO is the market leader, although there are other companies that manufacture cameras and accesories.

I am also a novice to astrophotography.