Connecting

Hi!
I am connecting via aerial and rgb scarts. When I follow instructions in manual requiring scart from cable box to dvd combi to tv, and aerial to cable then combi only the picture quality is poor. So I connected additional aerial from combi to tv and bicture got better. But then I couldn't watch the cable programmes on screen without switching off the power on the combi, so attached another scart from cable direct to other scart socket on tv but again could only get the cable channels with combi power off. The screen picture is better but not as good as it was before deciding to attach a recorder. I now have all these connections attached, 3 remote controls and am confused